TITLE OF THE INVENTION
Novel Sulfonyldiazomethanes , Photoacid Generators, Resist
Compositions, and Patterning Process
5
This invention relates to novel sulf onyldiazomethane
compounds, photoacid generators for resist compositions,
resist compositions comprising the photoacid generators, and
a patterning process using the same. The resist compositions,
10 especially chemical amplification type resist compositions
are sensitive to such radiation as UV, deep UV, electron
beams, x-rays, excimer laser beams, Y -ra Y s ' and synchrotron
radiation and suitable for the microf abrication of integrated
circuits .
15
BACKGROUND OF THE INVENTION
While a number of efforts are currently being made to
achieve a finer pattern rule in the drive for higher
20 integration and operating speeds in LSI devices,
deep-ultraviolet lithography is thought to hold particular
promise as the next generation in microf abrication technology.
One technology that has attracted a good deal of
attention recently utilizes as the deep UV light source a
25 high-intensity KrF excimer laser, especially an ArF excimer
laser featuring a shorter wavelength. There is a desire to
have a microf abrication technique of finer definition by
combining exposure light of shorter wavelength with a resist
material having a higher resolution.
30 In this regard, the recently developed, acid-catalyzed,
chemical amplification type resist materials are expected to
comply with the deep UV lithography because of their many
advantages including high sensitivity, resolution and dry
etching resistance. The chemical amplification type resist
35 materials include positive working materials that leave the
unexposed areas with the exposed areas removed and negative
-l-
working materials that leave the exposed areas with the
unexposed areas removed.
In chemical amplification type, positive working,
resist compositions to be developed with alkaline developers,
5 an alkali -soluble phenol or a resin and/or compound in which
carboxylic acid is partially or entirely protected with
acid- labile protective groups (acid labile groups) is
catalytically decomposed by an acid which is generated upon
exposure, to thereby generate the phenol or carboxylic acid
10 in the exposed area which is removed by an alkaline developer.
Also, in similar negative working resist compositions, an
alkali- soluble phenol or a resin and/or compound having
carboxylic acid and a compound (crosslinking agent) capable
of bonding or crosslinking the resin or compound under the
15 action of an acid are crosslinked with an acid which is
generated upon exposure whereby the exposed area is converted
to be insoluble in an alkaline developer and the unexposed
area is removed by the alkaline developer.
On use of the chemical amplification type, positive
20 working, resist compositions, a resist film is formed by
dissolving a resin having acid labile groups as a binder and
a compound capable of generating an acid upon exposure to
radiation (to be referred to as photoacid generator) in a
solvent, applying the resist solution onto a substrate by a
25 variety of methods, and evaporating off the solvent
optionally by heating. The resist film is then exposed to
radiation, for example, deep UV through a mask of a
predetermined pattern. This is optionally followed by
post-exposure baking (PEB) for promoting acid-catalyzed
30 reaction. The exposed resist film is developed with an
aqueous alkaline developer for removing the exposed area of
the resist film, obtaining a positive pattern profile. The
substrate is then etched by any desired technique. Finally
the remaining resist film is removed by dissolution in a
35 remover solution or ashing, leaving the substrate having the
desired pattern profile.
-2-
The chemical amplification type, positive working,
resist compositions adapted for KrF excimer lasers generally
use a phenolic resin, for example, polyhydroxystyrene in
which some or all of the hydrogen atoms of phenolic hydroxyl
5 groups are protected with acid labile protective groups .
Iodonium salts, sulfonium salts, and bissulf onyldiazomethane
compounds are typically used as the photoacid generator. If
necessary, there are added additives, for example, a
dissolution inhibiting or promoting compound in the form of a
10 carboxylic acid and/or phenol derivative having a molecular
weight of up to 3,000 in which some or all of the hydrogen
atoms of carboxylic acid and/or phenolic hydroxyl groups are
protected with acid labile groups , a carboxylic acid compound
for improving dissolution characteristics, a basic compound
15 for improving contrast, and a surfactant for improving
coating characteristics .
Bissulf onyldiazomethanes as shown below are
advantageously used as the photoacid generator in chemical
amplification type resist compositions, especially chemical
20 amplification type, positive working, resist compositions
adapted for KrF excimer lasers because they provide a high
sensitivity and resolution and eliminate poor compatibility
with resins and poor solubility in resist solvents as found
with the sulfonium and iodonium salt photoacid generators .
25
-3-
Although these photoacid generators are highly
lipophilic and highly soluble in resist solvents, they have
poor affinity to or solubility in developers so that upon
development and/or resist removal, the photoacid generators
5 can be left on the substrate as insoluble matter (consisting
of the photoacid generator or a mixture thereof with the
resin) .
For example, upon development, the resist material
which has poor affinity to or solubility in a developer
10 deposits on developed spaces in the exposed area or on lines
in the unexposed area as foreign matter.
JP-A 3-103854 discloses bis( 4-methoxyphenylsulf onyl) -
diazomethane as a photoacid generator having a methoxy group
introduced therein. As long as we confirmed, the methoxy
15 group is not fully effective. The photoacid generator is
often left on the substrate as insoluble matter (consisting
of the photoacid generator or a mixture thereof with the
resin) upon development and/or resist film removal.
If unsubstituted bis (phenylsulf onyl ) diazomethane or
20 bis (cyclohexylsulf onyl) diazomethane having alkyl groups
instead of aryl groups is used in a resist material as the
photoacid generator for reducing lipophilic property,
resolution is deteriorated. If it is added in large amounts,
the problem of insoluble matter upon development and/or
25 resist film removal remains unsolved.
Aside from the countermeasure for foreign matter, JP-A
10-90884 discloses to introduce such an acid labile group as
t-butoxycarbonyloxy , ethoxyethyl or tetrahydropyranyl into
disulf onediazomethane for the purpose of improving the
30 contrast of positive resist material. We empirically found
that these compounds are unstable and ineffective for
eliminating the foreign matter upon development and resist
film removal.
Searching for a countermeasure to the foreign matter
35 problem, we already synthesized sulf onyldiazomethanes having
an acyl group (e.g., acetyl) or methanesulf onyl group
introduced therein and found that they were useful as the
-4-
photoacid generator in chemical amplification type resist
composition. Since these arylsulf onyldiazomethanes having an
acyl group or methanesulf onyl group introduced therein lack
stability under basic conditions during their synthesis , the
5 yield of diazo formation is sometimes low. See JP-A
2001-055373 and JP-A 2001-106669.
It is known from JP-A 8-123032 to use two or more
photoacid generators in a resist material. JP-A 11-72921
discloses the use of a radiation-sensitive acid generator
10 comprising in admixture a compound which generates a sulfonic
acid having at least three fluorine atoms upon exposure to
radiation and a compound which generates a fluorine atom- free
sulfonic acid upon exposure to radiation, thereby improving
resolution without inviting nano-edge roughness and film
15 surface roughening. JP-A 11-38604 describes that a resist
composition comprising an asymmetric bissulf onyldiazomethane
such as a bissulf onyldiazomethane having alkylsulf onyl and
arylsulfonyl groups or a bissulf onyldiazomethane having
arylsulf onyl and alkoxy- substituted arylsulfonyl groups and a
20 polyhydroxystyrene derivative having acid labile groups as
the polymer has a resolution at least comparable to prior art
compositions, a sufficient sensitivity and significantly
improved heat resistance. However, we empirically found that
these resist compositions are unsatisfactory in resolution
25 and in the effect of eliminating the foreign matter on the
pattern upon development . From the synthetic and industrial
standpoints, it is difficult to obtain bilaterally asymmetric
bissulf onyldiazomethanes .
Aside from the above-discussed problem of insoluble
30 matter upon development and/or removal, there is also a
problem that the pattern profile often changes when the
period from exposure to post-exposure baking (PEB) is
prolonged, which is known as post-exposure delay (PED). Such
changes frequently reveal as a slimming of the line width of
35 unexposed areas in the case of chemical amplification type
positive resist compositions using acetal and analogous acid
labile groups, and as a thickening of the line width of
-5-
unexposed areas in the case of chemical amplification type
positive resist compositions using tert-butoxycarbonyl
(t-BOC) and analogous acid labile groups. Since the period
from exposure to PEB is often prolonged for the operational
5 reason, there is a desire to have a stable resist composition
which is free from such changes, that is, has PED stability.
In some resist processes, baking is performed at far
higher temperatures (e.g., 130° C) than the customary baking
temperature of 120° C or below as disclosed in JP-A 6-266112.
10 In this case, the bissulf onyldiazomethanes shown above by
structural formulae can be thermally decomposed to generate
acids due to their low heat resistance so that acidolysis
takes place everywhere regardless of whether the areas are
exposed or unexposed, failing in pattern formation.
15 The solubility of photosensitive agents or photoacid
generators was the problem from the age when quinonediazide
photosensitive agents were used in non-chemical amplification
type resist materials. Specific considerations include the
solubility of photoacid generators in resist solvents, the
20 compatibility of photoacid generators with resins, the
solubility (or affinity) of photo-decomposed products after
exposure and PEB and non- decomposed compound (photoacid
generator) in a developer, and the solubility of the
photoacid generator and photo-decomposed products thereof in
25 a remover solvent upon resist removal or peeling. If these
factors are poor, there can occur problems including
precipitation of the photoacid generator during storage,
difficulty of filtration, uneven coating, striation, abnormal
resist sensitivity, and foreign matter, left-over and
30 staining on the pattern and in spaces after development.
The photoacid generator in resist material is required
to meet a fully high solubility in (or compatibility with) a
resist solvent and a resin, good storage stability,
non-toxicity, effective coating, a well-defined pattern
35 profile, PED stability, no foreign matter left during pattern
formation after development and upon resist removal, and heat
resistance. The conventional photoacid generators.
-6-
r
especially diazodisulf one photoacid generators do not meet
all of these requirements.
As the pattern of integrated circuits becomes finer in
these days, a higher resolution is, of course, required, and
5 the problem of foreign matter after development and resist
removal becomes more serious .
SUMMARY OF THE INVENTION
An object of the invention is to provide a novel
10 sulf onyldiazomethane for use in a resist composition,
especially of the chemical amplification type, such that the
resist composition minimizes the foreign matter left after
coating, development and resist removal, has satisfactory
heat resistance, and ensures a well-defined pattern profile
15 after development. Another object of the invention is to
provide a photoacid generator for resist compositions, a
resist composition comprising the photoacid generator, and a
patterning process using the same.
We have found that by using a sulf onyldiazomethane
20 compound of the general formula (1), especially formula (la),
to be defined below, as the photoacid generator in a resist
composition, there are achieved a number of advantages
including dissolution, storage stability, effective coating,
minimized line width variation or shape degradation during
25 long-term PED, minimized foreign matter left after coating,
development and resist removal, satisfactory heat resistance,
a well-defined pattern profile after development, and a high
resolution enough for microf abrication , especially by deep UV
lithography. Better results are obtained when a
30 sulf onyldiazomethane compound of the formula (1), especially
formula (la), is used as the photoacid generator in a
chemical amplification type resist composition, typically
chemical amplification positive type resist composition
comprising a resin which changes its solubility in an
35 alkaline developer under the action of an acid as a result of
scission of C-O-C linkages. The composition exerts its
-7-
r
effect to the maximum extent when processed by deep UV
lithography.
In a first aspect, the invention provides a
sulf onyldiazomethane compound having the following general
5 formula ( 1 ) .
Herein R is each independently a substituted or unsubstituted
straight, branched or cyclic alkyl group of 1 to 4 carbon
atoms, G is S0 2 or CO, R 3 is a substituted or unsubstituted
io straight, branched or cyclic alkyl group of 1 to 10 carbon
atoms or a substituted or unsubstituted aryl group of 6 to 14
carbon atoms, p is 1 or 2 , q is 0 or 1, satisfying p+q = 2, m
is an integer of 3 to 11, and k is an integer of 0 to 4, with
the proviso that in the event k is at least 1, at least one
15 of R associated with k may bond with the R at the 4 -position
to form a cyclic structure with the carbon atoms on the
benzene ring to which these R's are attached, and then, these
two R f s bond together to form an alkylene group of 3 to 4
carbon atoms .
20 Typical sulf onyldiazomethane compounds have the
following general formula (la).
R R
wherein R is each independently a substituted or
unsubstituted straight, branched or cyclic alkyl group of 1
25 to 4 carbon atoms, and m is an integer of 3 to 11.
In a second aspect, the invention provides a photoacid
generator for a chemical amplification type resist
-8-
r
composition comprising the sulf onyldiazomethane compound of
formula ( 1 ) or ( la ) .
In a third aspect, the invention provides a chemical
amplification type resist composition comprising (A) a resin
5 which changes its solubility in an alkaline developer under
the action of an acid, (B) the sulf onyldiazomethane compound
of formula (1) or (la) which generates an acid upon exposure
to radiation, and optionally, (C) a compound capable of
generating an acid upon exposure to radiation, other than
10 component (B). The resist composition may further contain
(D) a basic compound, (E) an organic acid derivative, and an
organic solvent.
The resin (A) typically has such substituent groups
having C-O-C linkages that the solubility in an alkaline
15 developer changes as a result of scission of the C-O-C
linkages under the action of an acid.
In a preferred embodiment, the resin (A) is a polymer
containing phenolic hydroxyl groups in which hydrogen atoms
of the phenolic hydroxyl groups are substituted with acid
20 labile groups of one or more types in a proportion of more
than 0 mol% to 80 mol% on the average of the entire hydrogen
atoms of the phenolic hydroxyl groups , the polymer having a
weight average molecular weight of 3,000 to 100,000.
More preferably, the resin (A) is a polymer comprising
25 recurring units of the following general formula (2a):
R 4 R 4
-(CH 2 -C)— -(CH 2 -C)^ (2a)
(OH) y (R 5 ) x (QR 6 ) y (R 5 ) x
wherein R 4 is hydrogen or methyl, R 5 is a straight, branched
or cyclic alkyl group of 1 to 8 carbon atoms , x is 0 or a
positive integer, y is a positive integer, satisfying x+y =s
30 5, R 6 is an acid labile group, S and T are positive integers.
-9-
satisfying 0 < T/(S+T) <; 0.8, wherein the polymer contains
units in which hydrogen atoms of phenolic hydroxy 1 groups are
partially substituted with acid labile groups of one or more
types, a proportion of the acid labile group-bearing units is
on the average from more than 0 mol% to 80 mol% based on the
entire polymer, and the polymer has a weight average
molecular weight of 3,000 to 100, 000 .
In another preferred embodiment, the resin (A) is a
polymer comprising recurring units of the following general
formula ( 2a' ) :
R 4 R 4
I I
-(CH 2 -C)^j (CH 2 -C)—
J 1 (20
</^OR 6a
(OH) y (R 5 ) x (OR 6 ) y (R 5 ) x
wherein R 4 is hydrogen or methyl, R 5 is a straight, branched
or cyclic alkyl group of 1 to 8 carbon atoms , R 6 is an acid
labile group, R 6a is hydrogen or an acid labile group, at
least some of R 6a being acid labile groups, x is 0 or a
positive integer, y is a positive integer, satisfying x+y ^
5, M and N are positive integers, L is 0 or a positive
integer, satisfying 0 < N/(M+N+L) <: 0 . 5 and 0 < (N+L)/(M+N+L)
<s 0.8, wherein the polymer contains on the average from more
than 0 mol% to 50 mol% of those units derived from acrylate
and methacrylate , and also contains on the average from more
than 0 mol% to 80 mol% of acid labile group-bearing units,
based on the entire polymer, and the polymer has a weight
average molecular weight of 3,000 to 100,000.
In a further preferred embodiment, the resin (A) is a
polymer comprising recurring units of the following general
formula ( 2a" ) :
-10-
R 4 R 4 R 4
(CH 2 -C)x fCH-CH"^ (CH 2 ~C) r -(CH 2 -C)- fCH-CHV
CT^OR 6a
Q
(OH) y (R 5 ) x {OW)yy (R 5 ) x (OR 6 ) y (R 5 ) x (OR% (R^x
(2a")
wherein R 4 is hydrogen or methyl, R 5 is a straight, branched
or cyclic alkyl group of 1 to 8 carbon atoms, R 6 is an acid
labile group, R 6a is hydrogen or an acid labile group, at
5 least some of R 6a being acid labile groups, x is 0 or a
positive integer, y is a positive integer, satisfying x+y £
5, yy is 0 or a positive integer, satisfying x+yy <; 5, A and
B are positive integers, C, D and E each are 0 or a positive
integer, satisfying 0 < (B+E) / ( A+B+C+D+E) <; 0 . 5 and 0 <
10 (C+D+E)/(A+B+C+D+E) =s 0.8, wherein the polymer contains on
the average from more than 0 mol% to 50 mol% of those units
derived from indene and/or substituted indene, and also
contains on the average from more than 0 mol% to 80 mol% of
acid labile group-bearing units, based on the entire polymer,
15 and the polymer has a weight average molecular weight of
3,000 to 100,000.
In these preferred embodiments, the acid labile group
is selected from the class consisting of groups of the
following general formulae (4) to (7), tertiary alkyl groups
20 of 4 to 20 carbon atoms, trialkylsilyl groups whose alkyl
moieties each have 1 to 6 carbon atoms, oxoalkyl groups of 4
to 20 carbon atoms, and aryl-substituted alkyl groups of 7 to
20 carbon atoms.
-11-
O— R 12 (4) — (CH 2 )— C— O— R 13 (5)
R 11
Herein R 10 and R 11 each are hydrogen or a straight, branched
or cyclic alkyl having 1 to 18 carbon atoms, and R 12 is a
monovalent hydrocarbon group of 1 to 18 carbon atoms which
5 may contain a heteroatom, a pair of R 10 and R 11 , R 10 and R 12 , or
R 11 and R 12 may together form a ring, with the proviso that
R 10 , R 11 , and R 12 each are a straight or branched alkylene of 1
to 18 carbon atoms when they form a ring,
R 13 is a tertiary alkyl group of 4 to 20 carbon atoms,
10 a trialkysilyl group in which each of the alkyls has 1 to 6
carbon atoms, an oxoalkyl group of 4 to 20 carbon atoms, or a
group of the formula (4), z is an integer of 0 to 6 ,
R 14 is a straight, branched or cyclic alkyl group of 1
to 8 carbon atoms or an aryl group of 6 to 20 carbon atoms
15 which may be substituted, h is 0 or 1, i is 0 , 1, 2 or 3 ,
satisfying 2h+i = 2 or 3,
R 15 is a straight, branched or cyclic alkyl group of 1
to 8 carbon atoms or an aryl group of 6 to 20 carbon atoms
which may be substituted, R 16 to R 25 are each independently
20 hydrogen or a monovalent hydrocarbon group of 1 to 15 carbon
atoms which may contain a heteroatom, any two of R 16 to R 25 ,
taken together, may form a ring, each of the ring- forming two
of R 16 to R 25 is a divalent hydrocarbon group of 1 to 15
carbon atoms which may contain a heteroatom, or two of R 16 to
25 R 25 which are attached to adjoining carbon atoms may bond
together directly to form a double bond.
-12-
Preferably, the resist composition contains a
propylene glycol alkyl ether acetate, an alkyl lactate or a
mixture thereof as the organic solvent .
Also contemplated herein is a process for forming a
5 pattern, comprising the steps of applying the resist
composition onto a substrate to form a coating; heat treating
the coating and exposing the coating to high energy radiation
with a wavelength of up to 300 nm or electron beam through a
photomask; optionally heat treating the exposed coating, and
10 developing the coating with a developer.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Sulf onvldiazomethane
In the first aspect of the invention, novel
15 sulf onyldiazomethane compounds having a long-chain alkoxyl
group are provided. They are represented by the general
formula ( 1 ) .
Herein R is each independently a substituted or unsubstituted
20 straight, branched or cyclic alkyl group of 1 to 4 carbon
atoms. G is S0 2 or CO. R 3 is a substituted or unsubstituted
straight, branched or cyclic alkyl group of 1 to 10 carbon
atoms or a substituted or unsubstituted aryl group of 6 to 14
carbon atoms. The subscript p is 1 or 2, q is 0 or 1 ,
25 satisfying p+q = 2 , m is an integer of 3 to 11, and k is an
integer of 0 to 4 . In the event k is at least 1, at least
one of R associated with k may bond with the R at the
4 -position to form a cyclic structure with the carbon atoms
on the benzene ring to which these R's are attached, and then,
30 these two R's bond together to form an alkylene group of 3 or
4 carbon atoms.
-13-
Preferred among the sulf onyldiazomethane compounds of
formula (1) are sulf onyldiazomethane compounds having
long-chain alkoxyl groups of the following general formula
Herein R is each independently a substituted or unsubstituted
straight, branched or cyclic alkyl group of 1 to 4 carbon
atoms, and m is an integer of 3 to 11.
In formulae (1) and (la), R may be the same or
different and stands for substituted or unsubstituted,
straight, branched or cyclic alkyl groups of 1 to 4 carbon
atoms, for example, methyl, ethyl, n-propyl, sec-propyl,
cyclopropyl, n-butyl, sec-butyl, iso-butyl, tert -butyl,
2-methoxyethyl and trif luoromethyl . A plurality of R groups
may bond together to form a cyclic structure. In one
example, a tetramethylene or trimethylene group is attached
at the 4 , 5-positions relative to the sulfonyl to form a
cyclic structure. Of these, methyl, ethyl, n-propyl,
isopropyl and tert -butyl are preferred, with tert -butyl being
most preferred.
The subscript k is an integer of 0 to 3, and
preferably 0, 1 or 2 . The substitution position of R
associated with k is arbitrary.
R 3 stands for substituted or unsubstituted, straight,
branched or cyclic alkyl groups of 1 to 10 carbon atoms or
substituted or unsubstituted aryl groups of 6 to 14 carbon
atoms. Illustrative, non- limiting, examples of the straight,
branched or cyclic alkyl groups include methyl, ethyl,
n-propyl, sec-propyl, n-butyl, sec-butyl, iso-butyl,
tert -butyl, n-pentyl, sec-pentyl, cyclopentyl, n-hexyl, and
cyclohexyl. Illustrative, non- limiting, examples of the
substituted or unsubstituted aryl groups include phenyl.
(la).
(la)
-14-
4-methylphenyl, 4-ethylphenyl , 4-methoxyphenyl,
4 - ter t - bu ty lpheny 1 , 4 - 1 er t - but oxyphenyl , 4 - cyclohexy lpheny 1 ,
4 - cyclohexyloxypheny 1 , 2 , 4 - dimethylphenyl ,
2,4,6- trimethylphenyl , 2 , 4 , 6 - triisopropylphenyl ,
1-naphthyl and 2-naphthyl. Of these, tert -butyl, cyclohexyl,
4-methylphenyl, 2 , 4 -dimethylphenyl and 4-tert-butylphenyl are
preferred, G stands for S0 2 or CO. SO z is preferred.
It is noted that the substituted alkyl groups include
halogenated alkyl groups (e.g., chloro or f luoro-substituted
ones), carbonyl-containing alkyl groups, and alkyl groups
having a carbonyl group protected with an acetal (ketal) .
The substituted aryl groups include halogenated aryl groups
(e.g., chloro or f luoro-substituted ones) and straight,
branched or cyclic alkoxy group-substituted aryl groups.
Specific examples include 2 , 4-dif luorophenyl,
4-trif luoromethylphenyl, and groups of the following formulae.
(CH 2 ) 2
The subscript p is equal to 1 or 2, q is equal to 0 or
I, satisfying p+q = 2. The subscript m is an integer of 3 to
II, preferably an integer of 3 to 6 as long as the boiling
point of intermediate reactants is concerned.
The sulf onyldiazomethane compounds can be synthesized
by the following method although the synthesis method is not
limited thereto.
Reference is first made to a sulf onyldiazomethane
compound of formula (1) wherein p=2, that is, a symmetric
bissulf onyldiazomethane compound. It is desirably
synthesized by condensing a substituted thiophenol with
dichloromethane under basic conditions as disclosed in JP-A
3-103854. More specifically, a long chain alkoxyl- containing
thiophenol such as 2- (n-hexyloxy) -5-tert-butylthiophenol is
-15-
condensed with dichloromethane in an alcohol solvent such as
methanol or ethanol in the presence of a base such as sodium
hydroxide or potassium hydroxide, obtaining a formaldehyde
bis ( alkoxyphenylthio ) acetal .
20
CH 3 (CH 2 ) m O / CH 3 (CH 2 ) m O
CH2CI2
(R)j^ ) — f basic conditions
R
Herein, R, m and k are as defined above.
Alternatively, a substituted thiophenol is condensed
with a formaldehyde (typically paraformaldehyde) under acidic
conditions such as sulfuric acid or trif luoromethanesulf onic
10 acid.
In the case of p=l, that is, an asymmetric
sulf onyldiazomethane compound, reaction is effected between a
halomethyl thioether and an alkoxy- substituted thiophenol.
In the case of sulf onylcarbonyldiazomethane , reaction is
15 conducted between an cc-halomethylketone and an
alkoxy- substituted thiophenol. The halomethyl thioether can
be prepared from a corresponding thiol, formaldehyde and
hydrogen chloride (see J. Am. Chem. Soc, 86, 4383 (1964), J.
Am. Chem. Soc, 67, 655 (1945), and USP 2,354,229).
R 3 SCH 2 X * — 1
basic conditions
CH 3 (CH 2 ) m O
SCH 2 SR 3
R
CH 3 (CH 2 ) m O CH 3 (CH 2 ) m O
R 3 COCH 2 X
SH ^~ ^-"^ V /— SCH 2 COR J
basic conditions
(R) k ^>=/
R
Herein, R, R 3 , m and k are as defined above, and X is a
halogen atom.
-16-
Further, the product is oxidized with an oxidant such
as aqueous hydrogen peroxide in the presence of sodium
tungstate etc. as described in JP-A 4-211258, yielding a
corresponding sulf onylmethane .
H 2 0 2 or
other oxidant
H 2 0 2 or
other oxidant
H 2 0 2 or
other oxidant
SCH 2 COR J
CH 3 (CH 2 ) m O \
CH 3 (CH 2 ) m O
f ^— S0 2 — CH 2 S0 2 R 3
S0 2 — CH 2 COR J
Herein, R, R 3 , m and k are as defined above.
This product is reacted with p- toluenesulf onylazide ,
p-dodecylbenzenesulf onylazide or p-acetamidobenzenesulf onyl-
azide under basic conditions into a diazo form, yielding the
end sulf onyldiazomethane .
/ CH^CH^O
SO.H-CHn
CH 3 (CH 2 ) m O
S0 2 — CH 2 S0 2 R 3
TSN 3 or other
diazo-forming
agent
TSN 3 or other
diazo-forming CH 3 (CH 2 )„jO
agent
SO,-r-CN,
C, 7— S0 2 — CS0 2 R 3
(R)rw
TSN 3 or other
diazo-forming CH 3 (CH 2 ) m O
S0 2 — CH 2 COR J
agent
N,
<f, >— S0 2 — CCOR 3
R
•17-
Herein, R, R 3 , m and k are as defined above.
It is noted that the synthesis of alkoxy-substituted
thiophenols is not critical. They can be synthesized by
converting an alkoxybenzene with chlorosulf uric acid,
5 sulfuric acid/acetic anhydride or the like to a substituted
benzene sulfonic acid, then converting it with chlorosulf uric
acid, thionyl chloride or the like to a substituted benzene
sulfonyl chloride, and reducing it with aluminum lithium
hydride, hydrochloric acid/ zinc or the like as shown below.
CHaCCH^O CH 3 (CH 2 ) m O LL ^ H < CH 3 (CH 2 ) m O
Zn/HCl / 1
-so 2 ci ► % y — sh
10
Herein R, m and k are as defined above.
Alternatively, a halogenated alkoxybenzene is treated
with metallic magnesium to form a Grignard reagent, which is
reacted with sulfur and acidified. See Romeo B. Wagner and
15 Harry D. Zook, Synthetic Organic Chemistry, John Wiley &
Sons, Inc., 1965, 778-781.
Mg S8 H+
► ►
Herein R, m and k are as defined above, and X is a halogen
atom.
20 The halogenated alkoxybenzene can be synthesized by
reacting a phenol derivative with CH 3 (CH 2 ) m X under basic
conditions , followed by reaction with halogen such as
bromine. Exemplary of suitable phenol derivatives are
p-cresol , 4-ethylphenol , 4 -isopropylphenol ,
25 4-tert-butylphenol, 4- ( 2 -methoxyethyl) phenol,
5 , 6 , 7 , 8-tetrahydro-2-naphthol , and 5-indanol, with
4-tert-butylphenol being preferred.
-18-
CH 3 (CH 2 ) m O
CH 3 (CH2) m O
CH 3 (CH 2 ) m X
basic conditions
Herein R, m and k are as defined above, and X is a halogen
atom.
Examples of the sulf onyldiazomethanes of formulae (1)
and (la) include those of the following structures, but are
not limited thereto.
CH 3 (CH 2 ) m O 0(CH 2 ) m CH 3
O N 2 0 \=\
CH 3 (CH 2 ) m O
Q(CH 2 ) m CH 3
CH 3 (CH 2 ) m O
q(CH 2 )„CH 3
CH 3 (CHj)„,0 CXCH^CHj
-c °
CH 3 (CH 2 ) m O 0(CH 2 )„CH 3
CH 3 (CH 2 ) m O
/=< O N 2 O . .
CH 3 (CH 2 ) m O
CH 3 (CH 2 ) m O
/=< O N 2 0
' \ ii ii ^ ii
II 2 II / \
CH 3 (CH 2 ) m O
=< 0 N 2 0
\ ii ii 1 n
s-c-s
II II
o o
CH 3 (CH 2 ) m O
CH 3 (CH 2 ) m O
-s-c-s
II II
o o
-19-
CH 3 (CH 2 ) m O
CH 3 (CH 2 ) m O
/=< O N 2 0
/ \ ii ii z n
V^H- C - C -
CH 3 (CH 2 ) ra O
CH 3 (CH 2 ) m O
O N 2 0
x ii ii ii
s-c-c-
CH 3 (CH 2 ) m O
CH 3 (CH 2 ) m O
/=< O N 2 0
' \ ii ii z n
CH 3 (CH 2 ) m O
/=< O N 2 O
\ n ii z n
\ /-r c - c
CH 3 (CH 2 ) m O
O N 2 0
ii ii z n
CH 3 (CH 2 ) m O
/ < O N 2 0
/ \ n n z ii
y^Hr c - c
\ /
CH 3 (CH 2 ) m O
/=< O N 2 0
ii ii z ii
-s-c-c
CH 3 (CH 2 ) m O
/=( O N 2 O
\ ii n z n
\ /
CH 3 (CH 2 ) m O
It is noted that m is an integer of 3 to 11.
The sulf onyldiazome thane compounds of formula (1) or
(la) are useful as the photoacid generator in resist
materials, especially chemical amplification type resist
materials, which are sensitive to radiation such as
ultraviolet, deep ultraviolet, electron beams, x-rays.
-20-
excimer laser light, y-rays, and synchrotron radiation, for
use in the microf abrication of integrated circuits.
Resist composition
5 The resist compositions of the invention contain one
or more of the sulf onyldiazomethane compounds of formula (1)
or (la). The resist compositions may be either positive or
negative working although they are preferably of the chemical
amplification type. The resist compositions of the invention
10 include a variety of embodiments,
1) a chemically amplified positive working resist
composition comprising (A) a resin which changes its
solubility in an alkaline developer under the action of an
acid, (B) a sulf onyldiazomethane compound capable of
15 generating an acid upon exposure to radiation represented by
the general formula (1) or (la), and (F) an organic solvent;
2) a chemically amplified positive working resist
composition of 1) further comprising (C) a photoacid
generator capable of generating an acid upon exposure to
20 radiation other than component (B);
3) a chemically amplified positive working resist
composition of 1) or 2) further comprising (D) a basic
compound;
4) a chemically amplified positive working resist
25 composition of 1 ) to 3 ) further comprising (E) an organic
acid derivative;
5) a chemically amplified positive working resist
composition of 1) to 4) further comprising (G) a compound
with a molecular weight of up to 3,000 which changes its
30 solubility in an alkaline developer under the action of an
acid;
6) a chemically amplified negative working resist
composition comprising (B) a sulf onyldiazomethane compound
capable of generating an acid upon exposure to radiation
35 represented by the general formula (1) or (la), (F) an
organic solvent, (H) an alkali- soluble resin, and (I) an acid
-21-
crosslinking agent capable of forming a crosslinked structure
under the action of an acid;
7) a chemically amplified negative working resist
composition of 6) further comprising (C) another photoacid
5 generator;
8) a chemically amplified negative working resist
composition of 6) or 7 ) further comprising (D) a basic
compound; and
9) a chemically amplified negative working resist
10 composition of 6) to 8) further comprising (J) an alkali
soluble compound having a molecular weight of up to 2,500;
but not limited thereto.
Now the respective components are described in detail.
Component (A)
15 Component (A) is a resin which changes its solubility
in an alkaline developer solution under the action of an acid.
It is preferably, though not limited to, an alkali- soluble
resin having phenolic hydroxyl and/or carboxyl groups in
which some or all of the phenolic hydroxyl and/or carboxyl
20 groups are protected with acid- labile protective groups
having a C-O-C linkage.
The alkali- soluble resins having phenolic hydroxyl
and/ or carboxyl groups include homopolymers and copolymers of
p- hydroxys tyrene , m- hydroxys tyrene , a- methyl -p- hydroxys tyrene ,
25 4 -hydroxy- 2 -methyls tyrene , 4 -hydroxy- 3 -methylstyrene ,
hydroxyindene , methacrylic acid and acrylic acid, and
copolymers having a carboxylic derivative or diphenyl
ethylene introduced at the terminus of the foregoing polymers.
Also included are copolymers in which units free of
30 alkali-soluble sites such as styrene, a-methylstyrene,
acrylate, methacrylate , hydrogenated hydroxy styrene, maleic
anhydride, maleimide, substituted or unsubstituted indene are
introduced in addition to the above-described units in such a
proportion that the solubility in an alkaline developer may
35 not be extremely reduced. Substituents on the acrylates and
methacrylates may be any of the substituents which do not
undergo acidolysis. Exemplary substituents are straight,
-22-
branched or cyclic alkyl groups and aromatic groups such
as aryl groups, but not limited thereto.
Examples of the alkali- soluble resins or polymers are
given below. These polymers may also be used as the material
from which the resin (A) which changes its solubility in an
alkaline developer under the action of an acid is prepared
and as the alkali- soluble resin which serves as component (H)
to be described later. Examples include
poly (p-hydroxys tyrene) , poly (m-hydroxystyrene ) ,
poly( 4 -hydroxy- 2 -methyls tyrene) ,
poly ( 4 -hydroxy- 3 -methyls tyrene) ,
poly ( a-methyl - p -hydroxy s tyrene ) ,
partially hydrogenated p- hydroxys tyrene copolymers,
p-hydroxystyrene-a-methyl-p-hydroxystyrene copolymers ,
p-hydroxystyrene-a-methylstyrene copolymers ,
p- hydroxys tyrene -s tyrene copolymers ,
p- hydroxys tyrene -m-hydroxystyrene copolymers ,
p- hydroxys tyrene -s tyrene copolymers ,
p- hydroxys tyrene -indene copolymers ,
p- hydroxys tyrene- acrylic acid copolymers,
p-hydroxystyrene-methacrylic acid copolymers,
p-hydroxystyrene-methyl acrylate copolymers,
p- hydroxys tyrene -aery lie acid-methyl methacrylate copolymers,
p-hydroxystyrene-methyl methacrylate copolymers,
p-hydroxystyrene-methacrylic acid-methyl methacrylate
copolymers ,
poly (methacrylic acid), poly(acrylic acid),
acrylic acid-methyl acrylate copolymers,
methacrylic acid-methyl methacrylate copolymers,
acrylic acid-maleimide copolymers,
methacrylic acid-maleimide copolymers,
p- hydroxys tyrene -acrylic acid-maleimide copolymers , and
p-hydroxystyrene-methacrylic acid-maleimide copolymers, but
are not limited to these combinations.
Preferred are poly (p -hydroxy s tyrene ) ,
partially hydrogenated p- hydroxys tyrene copolymers.
-23-
p - hydr oxy s t yr ene - s tyr ene copolymers ,
p-hydroxystyrene-indene copolymers ,
p-hydroxystyrene-acrylic acid copolymers, and
p-hydroxystyrene-methacrylic acid copolymers.
Alkali -soluble resins comprising units of the
following formula (2), (2') or (2") are especially preferred.
Herein R 4 is hydrogen or methyl, R 5 is a straight, branched
or cyclic alkyl group of 1 to 8 carbon atoms, x is 0 or a
positive integer, y is a positive integer, satisfying x+y <s 5
M and N are positive integers, satisfying 0 < N/(M+N) ^ 0.5,
and A and B are positive integers, and C is 0 or a positive
integer, satisfying 0 < B/(A+B+C) «s 0.5.
The polymer of formula (2") can be synthesized, for
example, by effecting thermal polymerization of an
-24-
acetoxystyrene monomer, a tertiary alkyl (meth) acrylate
monomer and an indene monomer in an organic solvent in the
presence of a radical initiator, and subjecting the resulting
polymer to alkaline hydrolysis in an organic solvent for
5 deblocking the acetoxy group, for thereby forming a ternary
copolymer of hydroxystyrene, tertiary alkyl (meth) acrylate
and indene. The organic solvent used during polymerization
is exemplified by toluene, benzene, tetrahydrof uran , diethyl
ether and dioxane. Exemplary polymerization initiators
10 include 2,2' -azobisisobutyronitrile ,
2,2' -azobis ( 2 , 4-dimethylvaleronitrile) ,
dimethyl-2,2-azobis(2-methylpropionate) , benzoyl peroxide,
and lauroyl peroxide. Polymerization is preferably effected
while heating at 50 to 80° C. The reaction time is usually
15 about 2 to 100 hours, preferably about 5 to 20 hours.
Aqueous ammonia, triethylamine or the like may be used as the
base for the alkaline hydrolysis. For the alkaline
hydrolysis, the temperature is usually -20° C to 100° C,
preferably 0° C to 60° C, and the time is about 0.2 to 100
20 hours, preferably about 0.5 to 20 hours.
Herein ZZ is a divalent organic group selected from among CH 2 ,
25 CH(OH), CR 5 (OH), C=0 and C(OR 5 )(OH) or a trivalent organic
Also included are polymers having the dendritic or
hyperbranched polymer structure of formula (2"') below.
(2"')
-25-
group represented by -C(OH)=. Subscript F, which may be
identical or different, is a positive integer, and H is a
positive integer, satisfying 0.001 ^ H/(H+F) <; 0 . 1 , and XX is
1 or 2. R 4 , R 5 , x and y are as defined above.
5 The dendritic or hyperbranched polymer of phenol
derivative can be synthesized by effecting living anion
polymerization of a polymerizable monomer such as
4-tert-butoxystyrene and reacting a branching monomer such as
chloromethylstyrene as appropriate during the living anion
10 polymerization. For the detail of synthesis, reference is
made to JP-A 2000-344836.
The alkali- soluble resins or polymers should
preferably have a weight average molecular weight (Mw) of
3,000 to 100,000. Many polymers with Mw of less than 3,000
15 do not perform well and are poor in heat resistance and film
formation. Many polymers with Mw of more than 100,000 give
rise to a problem with respect to dissolution in the resist
solvent and developer. The polymer should also preferably
have a dispersity (Mw/Mn) of up to 3.5, and more preferably
20 up to 1.5. With a dispersity of more than 3.5, resolution is
low in many cases. Although the preparation method is not
critical, a poly(p-hydroxystyrene) or similar polymer with a
low dispersity or narrow dispersion can be synthesized by
living anion polymerization.
25 In the resist composition using the
sulf onyldiazomethane of formula (1), a resin having such
substituent groups with C-O-C linkages (acid labile groups)
that the solubility in an alkaline developer changes as a
result of severing of the C-O-C linkages under the action of
30 an acid, especially an alkali- soluble resin as mentioned
above is preferably used as component (A) . Especially
preferred is a polymer comprising recurring units of the
above formula (2) and containing phenolic hydroxyl groups in
which hydrogen atoms of the phenolic hydroxyl groups are
35 substituted with acid labile groups of one or more types in a
proportion of more than 0 mol% to 80 mol% on the average of
the entire hydrogen atoms of the phenolic hydroxyl group, the
-26-
polymer having a weight average molecular weight of 3,000 to
100,000.
Also preferred is a polymer comprising recurring units
of the above formula (2'), that is, a copolymer comprising
5 p- hydroxys tyrene and/or a-methyl-p-hydroxystyrene and acrylic
acid and/or methacrylic acid, wherein some of the hydrogen
atoms of the carboxyl groups of acrylic acid and/or
methacrylic acid are substituted with acid labile groups of
one or more types, and the units derived from acrylate and/or
10 methacrylate are contained in a proportion of more than 0
mol% to 50 mol%, on the average, of the copolymer, and
wherein some of the hydrogen atoms of the phenolic hydroxyl
groups of p- hydroxys tyrene and/or a-methyl-p -hydroxys tyrene
may be substituted with acid labile groups of one or more
is types. In the preferred copolymer, the units derived from
acrylate and/ or methacrylate and the units derived from
p- hydroxys tyrene and/or a-methyl-p-hydroxystyrene optionally
having acid labile groups substituted thereon are contained
in a proportion of more than 0 mol% to 80 mol%, on the
20 average, of the copolymer.
Alternatively, a polymer comprising recurring units of
the above formula (2"), that is, a copolymer comprising
p- hydroxys tyrene and/or a-methyl-p-hydroxystyrene and
substituted and/or unsubstituted indene, is preferred wherein
25 some of the hydrogen atoms of the phenolic hydroxyl groups of
p- hydroxys tyrene and/or a-methyl-p-hydroxystyrene are
substituted with acid labile groups of one or more types, and
some of the hydrogen atoms of the carboxyl groups of acrylic
acid and/or methacrylic acid are substituted with acid labile
30 groups of one or more types. Where the substituted indene
has hydroxyl groups, some of the hydrogen atoms of these
hydroxyl groups may be substituted with acid labile groups of
one or more types. In the preferred copolymer, the units
derived from p- hydroxys tyrene and/or a-methyl-p-hydroxy-
35 styrene having acid labile groups substituted thereon, the
units derived from acrylic acid and/or methacrylic acid
-27-
having acid labile groups substituted thereon, and the units
derived from indene having acid labile groups substituted
thereon are contained in a proportion of more than 0 mol% to
80 mol%, on the average, of the copolymer.
Exemplary and preferred such polymers are polymers or
high molecular weight compounds comprising recurring units
represented by the following general formula (2a), (2a') or
(2a") and having a weight average molecular weight of 3,000
to 100,000.
R
I
-(CH 2 -C)— -(CH 2 -C)—
(OH) y (R 5 ) x (QR 6 ) y (R 5 )x
(2a)
f f f
- (CH - (CH - Cft (CH- C) F
(OH) y (R\
OR 1
6a
(OR 6 ) y (R 5 ) x
(2a 1 )
R"
R«
I
R"
- (CH 2 - C)^ { CH- CH") i (CH 2 - Q- - (CH 2 - Q- k CH" CH^
(OH) y (R\ (OH),, (R 5 ) x
CT^OR'
(OR 6 ). (R 5 ) x (OR% (R 5 ):
(2a")
Herein, R 4 is hydrogen or methyl. R 5 is a straight,
branched or cyclic alkyl group of 1 to 8 carbon atoms .
Letter x is 0 or a positive integer, and y is a positive
-28-
integer, satisfying x+y <; 5 . R 6 is an acid labile group. S
and T are positive integers, satisfying 0 < T/(S+T) <s 0.8.
R 6a is hydrogen or an acid labile group, at least some of the
R 6a groups are acid labile groups . M and N are positive
5 integers, L is 0 or a positive integer, satisfying 0 <
N/(M+N+L) <; 0.5 and 0 < ( N+L ) / (M+N+L ) «s 0.5. The letter yy
is 0 or a positive integer, satisfying x+yy <s 5. A and B are
positive integers, C, D and E each are 0 or a positive
integer, satisfying 0 < (B+E) / (A+B+C+D+E) «s 0.5 and 0 <
10 (C+D+E)/(A+B+C+D+E) <; 0.8.
R 5 stands for straight, branched or cyclic C^g alkyl
groups, for example, methyl, ethyl, propyl, isopropyl,
n-butyl, isobutyl, tert -butyl, cyclohexyl and cyclopentyl.
With respect to the acid labile groups, where some of
15 the phenolic hydroxyl groups and some or all of the carboxyl
groups in the alkali-soluble resin are protected with acid
labile groups having C-O-C linkages, the acid labile groups
are selected from a variety of such groups . The preferred
acid labile groups are groups of the following general
20 formulae (4) to (7), tertiary alkyl groups of 4 to 20 carbon
atoms, preferably 4 to 15 carbon atoms, trialkylsilyl groups
whose alkyl groups each have 1 to 6 carbon atoms, oxoalkyl
groups of 4 to 20 carbon atoms, or aryl-substituted alkyl
groups of 7 to 20 carbon atoms.
O— R 12 (4) — (CH 2 )— C— O— R 13 (5)
R n
-29-
Herein R 10 and R 11 are independently hydrogen or
straight, branched or cyclic alkyl groups of 1 to 18 carbon
atoms, preferably 1 to 10 carbon atoms, for example, methyl,
ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl,
cyclopentyl, cyclohexyl, 2-ethylhexyl and n-octyl. R 12 is a
monovalent hydrocarbon group of 1 to 18 carbon atoms,
preferably 1 to 10 carbon atoms, which may have a hetero atom
(e.g., oxygen atom), for example, straight, branched or
cyclic alkyl groups, and such groups in which some hydrogen
atoms are substituted with hydroxyl, alkoxy, oxo, amino or
alkylamino groups. Illustrative examples of the substituted
alkyl groups are given below.
A pair of R 10 and R 11 , a pair of R 10 and R 12 , or a pair of
R 11 and R 12 , taken together, may form a ring. Each of R 10 , R 11
and R 12 is a straight or branched alkylene group of 1 to 18
carbon atoms, preferably 1 to 10 carbon atoms, when they form
a ring.
R 13 is a tertiary alkyl group of 4 to 20 carbon atoms,
preferably 4 to 15 carbon atoms, a trialkylsilyl group whose
alkyl groups each have 1 to 6 carbon atoms, an oxoalkyl group
of 4 to 20 carbon atoms or a group of formula (4). Exemplary
tertiary alkyl groups are tert-butyl, tert-amyl,
1, 1-diethylpropyl, 1-ethylcyclopentyl , 1-butylcyclopentyl ,
1- ethyl cyclohexyl , 1-butylcyclohexyl ,
1 - ethyl - 2 - cyclopentenyl , 1 - ethyl - 2 - cyclohexenyl ,
2 - methyl - 2 - adamantyl , 2 - ethyl - 2 - adamantyl and
1-adamantyl-l-methylethyl. Exemplary trialkylsilyl groups
are trimethylsilyl , triethylsilyl, and
dimethyl- tert -butylsilyl . Exemplary oxoalkyl groups are
(CH 2 ) 4 OH
-30-
3 - oxocyclohexyl , 4 -methyl - 2 - oxooxan - 4 -yl , and
5-methyl-5-oxooxolan-4-yl. Letter z is an integer of 0 to 6 .
R 14 is a straight, branched or cyclic alkyl group of 1
to 8 carbon atoms or substituted or unsubstituted aryl group
5 of 6 to 20 carbon atoms. Exemplary straight, branched or
cyclic alkyl groups include methyl, ethyl, propyl, isopropyl,
n-butyl, sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl,
cyclopentyl , cyclohexyl , cyclopentylmethyl , cyclopentylethyl ,
cyclohexylmethyl and cyclohexylethyl . Exemplary substituted
10 or unsubstituted aryl groups include phenyl, methylphenyl ,
naphthyl, anthryl, phenanthryl, and pyrenyl. Letter h is
equal to 0 or 1, i is equal to 0 , 1, 2 or 3 , satisfying 2h+i
= 2 or 3.
R 15 is a straight, branched or cyclic alkyl group of 1
15 to 8 carbon atoms or substituted or unsubstituted aryl group
of 6 to 20 carbon atoms, examples of which are as exemplified
for R 14 . R 16 to R 25 are independently hydrogen or monovalent
hydrocarbon groups of 1 to 15 carbon atoms which may contain
a hetero atom, for example, straight, branched or cyclic
20 alkyl groups such as methyl, ethyl, propyl, isopropyl,
n-butyl, sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl,
n-octyl, n-nonyl, n-decyl, cyclopentyl, cyclohexyl,
cyclopentylmethyl , cyclopentylethyl , cyclopentylbutyl ,
cyclohexylmethyl, cyclohexylethyl, and cyclohexylbutyl, and
25 substituted ones of these groups in which some hydrogen atoms
are substituted with hydroxyl, alkoxy, carboxy,
alkoxycarbonyl , oxo, amino, alkylamino, cyano, mercapto,
alkylthio, and sulfo groups. R 16 to R 25 , for example, a pair
of R 16 and R 17 , a pair of R 16 and R 18 , a pair of R 17 and R 19 , a
30 pair of R 18 and R 19 , a pair of R 20 and R 21 , or a pair of R 22 and
R 23 , taken together, may form a ring. When R 16 to R 26 form a
ring, they are divalent hydrocarbon groups of 1 to 15 carbon
atoms which may contain a hetero atom, examples of which are
the above -exemplified monovalent hydrocarbon groups with one
35 hydrogen atom eliminated. Also, two of R 16 to R 25 which are
attached to adjacent carbon atoms (for example, a pair of R 16
-31-
and R 18 , a pair of R 18 and R 24 , or a pair of R 22 and R 24 ) may
directly bond together to form a double bond.
Of the acid labile groups of formula (4), illustrative
examples of the straight or branched groups are given below.
— CH 2 — O-CH3 — CH 2 — 0-CH 2 -CH 3 — CH 2 — O— (CH 2 ) 2 -CH 3
CH 3
— CH 2 — 0-(CH 2 ) 3 — CH 3 — CH 2 — O— CH— CH 3
CH 3 CH 3 CH 3
— CH 2 — 0- C— CH 3 — CH— O— CH 3 — CH — O - CH 2 — CH 3
CH 3
1 1 1
CH 2 (CH 2 ) 2 CH 2
— CH— O— CH 3 — CH— O— CH 3 — CH— O— CH 2 — CH 3
CH 3 CH 3
I I
— CH— O— (CH2) 3 -CH 3 — CH— O— (CH 2 ) 2 -CH 3
CH-i CH3
1 1
CH 2 CH 2
— CH— O— (CH2) 3 -CH 3 — CH— O— (CH 2 ) 2 -CH 3
CH 3 CH 3
(CH,), (CH 2 ) 2
— CH— O— (CH 2 ) 3 -CH 3 — CH— 0— (CH 2 ) 2 -CH 3
CH
CH,
-CH-O-^Q -CH-O-
CH 3 CH 3
— C— O— CH 3 -C— 0-CH 2 — CH 3
I I
CH 2 CH 3 CH 2 CH 3
<^^-CH 2 0-C— ^^CH 2 CH 2 0-C—
H ^ H
CH 2 CH 3 CH 2 CH 3
O-O-C- <3-CH 2 0-C-
H H
-32-
Of the acid labile groups of formula (4), illustrative
examples of the cyclic groups include tetrahydrof uran-2-yl,
2 -methyltetrahydrof uran- 2 -yl , tetrahydropyran- 2 -yl and
2-methyltetrahydropyran-2-yl .
Illustrative examples of the acid labile groups of
formula (5) include tert-butoxycarbonyl ,
tert-butoxycarbonylmethyl, tert-amyloxycarbonyl ,
t ert - amyloxycarbony lmethyl , 1,1- die thylpropyloxycarbonyl ,
1 , 1- die thylpropyloxycarbony lmethyl ,
1 - ethylcyclopen tyloxycarbonyl ,
1 - ethylcyclopen tyloxycarbony lmethyl ,
1 - ethyl - 2 - cyclopent enyloxycarbony 1 ,
1 - ethyl - 2 - cyclopent enyloxycarbony lmethyl ,
1 - ethoxyethoxycarbony lmethyl ,
2 - tetrahydropyranyloxycarbony lmethyl , and
2 - tetrahydrof uranyloxycarbony lmethyl .
Illustrative examples of the acid labile groups of
formula (6) include 1-methylcyclopentyl, 1-ethylcyclopentyl,
1 - n-propylcyclopentyl , 1 - isopropylcyclopentyl ,
1-n-butylcyclopentyl, 1-sec-butylcyclopentyl ,
1-methylcyclohexyl , 1-ethylcyclohexyl ,
3- methyl-l-cyclopenten-3-yl , 3-ethyl-l-cyclopenten-3-yl ,
3 -methyl- 1 -cyclohexen- 3 -yl , 3 -ethyl- 1 - cyclohexen- 3 -yl , and
1-cyclohexyl-cyclopentyl •
Illustrative examples of the acid labile groups of
formula (7) are given below.
-33-
Exemplary of the tertiary alkyl group of 4 to 20
carbon atoms, preferably 4 to 15 carbon atoms, are tert-butyl,
ter t - amyl , 1,1- die thylpropyl , 1 - ethylcyclopentyl ,
1 - butyl cyclopenty 1 , 1 - e thy lcyclohexyl , 1 -butylcyclohexyl ,
1 - ethyl - 2 - cyclopent enyl , 1 - ethyl - 2 - cyclohexenyl ,
2 - methyl - 2 - adamantyl , 2 - ethyl - 2 - adamantyl ,
1-adamantyl-l-methylethyl, 3-ethyl-3-pentyl and
dimethylbenzyl .
Exemplary of the trialkylsilyl groups whose alkyl
groups each have 1 to 6 carbon atoms are trimethylsilyl ,
triethylsilyl, and tert-butyldimethylsilyl .
Exemplary of the oxoalkyl groups of 4 to 20 carbon
atoms are 3-oxocyclohexyl and groups represented by the
following formulae.
Exemplary of the aryl-substituted alkyl groups of 7 to
20 carbon atoms are benzyl, methylbenzyl , dimethylbenzyl,
diphenylmethyl , and 1,1- diphenylethyl .
In the resist composition comprising the
sulf onyldiazomethane as a photoacid generator, the resin (A)
which changes its solubility in an alkaline developer under
the action of an acid may be the polymer of formula (2) or
( 2 1 ) , (2") or ( 2 " 1 ) in which some of the hydrogen atoms of
the phenolic hydroxyl groups are crosslinked within a
molecule and/or between molecules, in a proportion of more
than 0 mol% to 50 mol%, on the average, of the entire
phenolic hydroxyl groups on the polymer, with crosslinking
groups having C-O-C linkages represented by the following
general formula (3). With respect to illustrative examples
and synthesis of polymers crosslinked with acid labile groups,
reference should be made to JP-A 11-190904.
-34-
R 7
-f O— R 9 -)^- O — AA- - O— ("R 9 - O-)
R°
I
I 7 "
I
* 8 _
a
(3)
Herein, each of R 7 and R 8 is hydrogen or a straight,
branched or cyclic alkyl group of 1 to 8 carbon atoms, or R 7
and R 8 , taken together, may form a ring, and each of R 7 and R 8
5 is a straight or branched alkylene group of 1 to 8 carbon
atoms when they form a ring. R 9 is a straight, branched or
cyclic alkylene group of 1 to 10 carbon atoms. Letter "b"
is 0 or an integer of 1 to 10. AA is an a-valent aliphatic
or alicyclic saturated hydrocarbon group, aromatic
10 hydrocarbon group or heterocyclic group of 1 to 50 carbon
atoms, which may be separated by a hetero atom and in which
some of the hydrogen atom attached to carbon atoms may be
substituted with hydroxyl, carboxyl, carbonyl or halogen.
Letter "a" is an integer of 1 to 7 .
15 Preferably in formula (3), R 7 is methyl, R 8 is hydrogen,
"a" is 1, "b" is 0, and AA is ethylene, 1,4-butylene or
1,4- cyclohexylene .
It is noted that these polymers which are crosslinked
within the molecule or between molecules with crosslinking
20 groups having C-O-C linkages can be synthesized by reacting a
corresponding non-crosslinked polymer with an alkenyl ether
in the presence of an acid catalyst in a conventional manner.
If decomposition of other acid labile groups proceeds
under acid catalyst conditions, the end product can be
25 obtained by once reacting the alkenyl ether with hydrochloric
acid or the like for conversion to a halogenated alkyl ether
and reacting it with the polymer under basic conditions in a
conventional manner.
Illustrative, non-limiting, examples of the alkenyl
30 ether include ethylene glycol divinyl ether, triethylene
glycol divinyl ether, 1 , 2 -propanediol divinyl ether,
1 . 3 - propanediol divinyl ether, 1 , 3-butanediol divinyl ether,
1 . 4- butanediol divinyl ether, neopentyl glycol divinyl ether.
-35
trimethylolpropane trivinyl ether, trimethylolethane trivinyl
ether, hexanediol divinyl ether, and
1,4- cyclohexanediol divinyl ether .
In the chemical amplification type positive resist
composition, the resin used as component (A) is as described
above while the preferred acid labile groups to be
substituted for phenolic hydroxyl groups are 1-ethoxyethyl,
1- ethoxypropyl , tetrahydrof uranyl , tetrahydropyranyl ,
tert -butyl , tert - amyl , 1 - ethylcyclohexyloxycarbonylmethyl ,
tert -butoxycarbonyl , tert -but oxycarbonylmethyl , and
substituents of formula (3) wherein R 7 is methyl, R 8 is
hydrogen, "a" is 1, "b" is 0, and AA is ethylene,
1,4-butylene or 1 , 4-cyclohexylene . Also preferably, the
hydrogen atoms of carboxyl groups of methacrylic acid or
acrylic acid are protected with substituent groups as
typified by tert -butyl, tert -amyl, 2-methyl-2-adamantyl ,
2 - ethyl - 2 - adamanty 1 , 1 - e thy lcyclopenty 1 , 1 - ethy lcyclohexy 1 ,
1 - cyclohexylcyclopen tyl , 1 - e thy lnorbornyl ,
tetrahydrof uranyl and tetrahydropyranyl.
In a single polymer, these substituents may be
incorporated alone or in admixture of two or more types . A
blend of two or more polymers having substituents of
different types is also acceptable.
The percent proportion of these substituents
substituting for phenol and carboxyl groups in the polymer is
not critical. Preferably the percent substitution is
selected such that when a resist composition comprising the
polymer is applied onto a substrate to form a coating, the
unexposed area of the coating may have a dissolution rate of
0.01 to 10 A/sec in a 2.38% tetramethylammonium hydroxide
(TMAH) developer.
On use of a polymer containing a greater proportion of
carboxyl groups which can reduce the alkali dissolution rate,
the percent substitution must be increased or
non- acid-decomposable substituents to be described later must
be introduced.
-36-
When acid labile groups for intramolecular and/or
intermolecular crosslinking are to be introduced , the percent
proportion of crosslinking substituents is preferably up to
20 mol%, more preferably up to 10 mol% , based on the entire
5 hydrogen atoms of phenolic hydroxyl groups. If the percent
substitution of crosslinking substituents is too high,
crosslinking results in a higher molecular weight which can
adversely affect dissolution, stability and resolution. It
is also preferred to further introduce another
10 non-crosslinking acid labile group into the crosslinked
polymer at a percent substitution of up to 10 mol% for
adjusting the dissolution rate to fall within the above
range .
In the case of poly (p -hydroxy styrene) , the optimum
15 percent substitution differs between a substituent having a
strong dissolution inhibitory action such as a
tert-butoxycarbonyl group and a substituent having a weak
dissolution inhibitory action such as an acetal group
although the overall percent substitution is preferably 10 to
20 40 mol%, more preferably 20 to 30 mol%, based on the entire
hydrogen atoms of phenolic hydroxyl groups in the polymer.
Polymers having such acid labile groups introduced
therein should preferably have a weight average molecular
weight (Mw) of 3,000 to 100,000. With a Mw of less than
25 3,000, polymers would perform poorly and often lack heat
resistance and film formability. Polymers with a Mw of more
than 100,000 would be less soluble in a developer and a
resist solvent .
Where non-crosslinking acid labile groups are
30 introduced, the polymer should preferably have a dispersity
(Mw/Mn) of up to 3.5, preferably up to 1.5. A polymer with a
dispersity of more than 3.5 often results in a low
resolution. Where crosslinking acid labile groups are
introduced, the starting alkali- soluble resin should
35 preferably have a dispersity (Mw/Mn) of up to 1.5, and the
dispersity is kept at 3 or lower even after protection with
crosslinking acid labile groups. If the dispersity is higher
-37-
than 3, dissolution, coating, storage stability and/or
resolution is often poor.
To impart a certain function, suitable substituent
groups may be introduced into some of the phenolic hydroxyl
5 and carboxyl groups on the acid labile group-protected
polymer. Exemplary are substituent groups for improving
adhesion to the substrate, non-acid-labile groups for
adjusting dissolution in an alkali developer, and substituent
groups for improving etching resistance. Illustrative,
10 non-limiting, substituent groups include 2 -hydroxy ethyl ,
2 -hydroxypropyl , methoxymethyl , methoxycarbonyl ,
ethoxycarbonyl , methoxycarbonylmethyl , ethoxycarbonylmethyl ,
4 -methyl - 2 - oxo - 4 - oxolanyl , 4 -methyl -2- oxo - 4 - oxanyl , methyl ,
ethyl, propyl, n-butyl, sec-butyl, acetyl, pivaloyl,
15 adamantyl, isobornyl, and cyclohexyl.
In the resist composition of the invention, the
above -described resin is added in any desired amount, and
usually 65 to 99 parts by weight, preferably 70 to 98 parts
by weight per 100 parts by weight of the solids in the
20 composition. The term "solids" is used to encompass all
components in the resist composition excluding the solvent.
Illustrative examples of the sulf onyldiazomethane
compounds of formulae (1) and (la) as the photoacid generator
(B) are as described above. Listing again, examples of
25 bilaterally symmetric bissulf onyldiazomethane include, but
are not limited to,
bis ( 2- (n-butyloxy ) -5-methylbenzenesulf onyl) diazomethane ,
bis ( 2 - ( n-pentyloxy ) - 5 -methylbenzenesulf onyl ) diazomethane ,
bis ( 2- (n-hexyloxy ) -5-methylbenzenesulf onyl) diazomethane ,
30 bis ( 2- (n-heptyloxy ) - 5-methylbenzenesulf onyl ) diazomethane ,
bis ( 2- (n-octyloxy ) -5-methylbenzenesulf onyl ) diazomethane ,
bis( 2- (n-nonyloxy) -5-methylbenzenesulf onyl) diazomethane,
bis ( 2- (n-butyloxy) - 5 -ethylbenzenesulf onyl) diazomethane,
bis( 2- (n-pentyloxy) - 5 -ethylbenzenesulf onyl) diazomethane,
35 bis ( 2 - ( n-hexyloxy ) - 5 - ethylbenzenesulf onyl ) diazomethane ,
bis( 2- (n-heptyloxy) -5 -ethylbenzenesulf onyl) diazomethane,
bis ( 2- (n-octyloxy) - 5 -ethylbenzenesulf onyl) diazomethane.
-38-
bis ( 2 - ( n-nonyloxy ) - 5 -ethylbenzenesulf onyl ) diazomethane ,
bis ( 2 - ( n-butyloxy ) - 5 - isopropylbenzenesulf onyl ) diazomethane ,
bis ( 2 - ( n - pentyloxy ) - 5 - is opropylbenzenesulf onyl ) diaz ome thane ,
bis ( 2 - ( n-hexyloxy ) - 5 - isopropylbenzenesulf onyl ) diazomethane ,
bis ( 2 - ( n-heptyloxy ) - 5 - isopropylbenzenesulf onyl ) diazomethane ,
bis ( 2- ( n-octyloxy ) - 5 -isopropylbenzenesulf onyl ) diazomethane ,
bis ( 2 - (n-nonyloxy ) - 5 -isopropylbenzenesulf onyl ) diazomethane ,
bis ( 2 - ( n-butyloxy ) - 5 - tert -butylbenzenesulf onyl ) diazomethane ,
bis ( 2 - ( n-pentyloxy ) - 5 - tert -butylbenzenesulf onyl ) diazomethane ,
bis ( 2 - ( n-hexyloxy ) - 5 - tert -butylbenzenesulf onyl ) diazomethane ,
bis ( 2 - ( n-heptyloxy ) - 5 - tert -butylbenzenesulf onyl ) diazomethane ,
bis ( 2 - (n-octyloxy ) - 5 - tert -butylbenzenesulf onyl ) diazomethane ,
bis ( 2 - ( n-nonyloxy ) - 5 - tert - butylbenzenesulf onyl ) diazomethane ,
etc. Of these, preferred are
bis ( 2 - ( n-butyloxy ) - 5 - tert -butylbenzenesulf onyl ) diazomethane ,
bis ( 2 - ( n-pentyloxy ) - 5 - tert -butylbenzenesulf onyl ) diazomethane ,
and bis(2- (n-hexyloxy) -5-tert-butylbenzenesulf onyl)diazo-
methane .
Examples of bilaterally asymmetric
sulf onyldiazomethane include, but are not limited to,
( 2- (n-butyloxy ) -5-methylbenzenesulf onyl) ( tert -butylsulf onyl ) -
diazomethane ,
( 2- (n-pentyloxy) -5-methylbenzenesulf onyl ) ( tert-butyl-
sulf onyl ) diazomethane ,
( 2- (n-hexyloxy) -5-methylbenzenesulf onyl) ( tert -butylsulf onyl) -
diazomethane ,
( 2- (n-butyloxy) -5-tert-butylbenzenesulf onyl) ( tert-butyl-
sulf onyl ) diazomethane ,
( 2- (n-pentyloxy) -5-tert-butylbenzenesulf onyl) ( tert -butyl-
sulf onyl ) diazomethane ,
(2- (n-hexyloxy) -5-tert-butylbenzenesulf onyl) (tert -butyl-
sulf onyl ) diazomethane ,
( 2- (n-butyloxy) -5-methylbenzenesulf onyl) ( cyclohexylsulf onyl) -
diazomethane ,
( 2- (n-pentyloxy) -5-methylbenzenesulf onyl ) (cyclohexyl-
sulf onyl ) diazomethane ,
( 2- (n-hexyloxy ) -5-methylbenzenesulf onyl) ( cyclohexylsulf onyl )
diazomethane ,
(2- (n-butyloxy) -5- tert-butylbenzenesulf onyl) (cyclohexyl-
sulf onyl ) diazomethane ,
( 2 - ( n-pentyloxy ) - 5 - tert -butylbenzenesulf onyl ) ( cyclohexyl-
sulf onyl ) diazomethane ,
( 2- (n-hexyloxy) - 5- tert-butylbenzenesulf onyl ) (cyclohexyl-
sulf onyl ) diazomethane ,
( 2- (n-butyloxy) - 5-methylbenzenesulf onyl ) ( 2 , 4-dimethylbenzene
sulf onyl ) diazomethane ,
(2- (n-pentyloxy) -5-methylbenzenesulf onyl) ( 2 , 4 -dimethyl -
benzenesulf onyl ) diazomethane ,
(2- (n-hexyloxy) -5-methylbenzenesulf onyl) ( 2 , 4-dimethylbenzene
sulf onyl ) diazomethane ,
(2- (n-butyloxy) -5-tert-butylbenzenesulf onyl) ( 2 , 4-dimethyl-
benzenesulf onyl ) diazomethane ,
( 2- (n-pentyloxy) -5- tert-butylbenzenesulf onyl ) ( 2 , 4- dimethyl -
benzenesulf onyl ) diazomethane ,
(2- (n-hexyloxy) -5-tert-butylbenzenesulf onyl) ( 2 , 4-dimethyl-
benzenesulf onyl ) diazomethane ,
(2- (n-butyloxy) - 5-methylbenzenesulf onyl ) ( 2- naphthalene -
sulf onyl ) diazomethane ,
(2- (n-pentyloxy) -5-methylbenzenesulf onyl) ( 2 -naphthalene -
sulf onyl ) diazomethane ,
( 2- (n-hexyloxy) -5-methylbenzenesulf onyl) ( 2 -naphthalene -
sulf onyl ) diazomethane ,
(2- (n-butyloxy) -5-tert-butylbenzenesulf onyl) ( 2 -naphthalene -
sulf onyl ) diazomethane ,
( 2 - ( n-pentyloxy ) - 5 - tert -butylbenzenesulf onyl ) ( 2 -naphthalene -
sulf onyl ) diazomethane ,
(2- (n-hexyloxy) -5-tert-butylbenzenesulf onyl) ( 2 -naphthalene -
sulf onyl ) diazomethane , etc .
Examples of the sulf onyl-carbonyldiazomethane include,
but are not limited to,
(2- (n-butyloxy) -5-methylbenzenesulf onyl) ( tert-butylcarbonyl)
diazomethane ,
( 2 - ( n-pentyloxy ) - 5 -methylbenzenesulf onyl ) ( tert - butyl -
carbonyl ) diazomethane ,
( 2 - ( n-hexyloxy ) - 5 -me thylbenzenesulf onyl ) ( tert -butylcarbonyl ) -
diazomethane,
( 2 - ( n-butyloxy ) - 5 - tert -butylbenzenesulf onyl ) ( tert -butyl-
carbonyl ) diazomethane ,
( 2 - ( n-pentyloxy ) - 5 - tert -butylbenzenesulf onyl ) ( tert -butyl-
carbonyl ) diazomethane ,
( 2 - ( n-hexyloxy ) - 5 - tert - butylbenzenesulf onyl ) ( tert -butyl -
carbonyl ) diazomethane ,
( 2- (n-butyloxy) -5 -methylbenzenesulf onyl) (benzenecarbonyl) -
diazomethane ,
( 2- (n-pentyloxy) -5-methylbenzenesulf onyl) (benzenecarbonyl) -
diazomethane ,
( 2- (n-hexyloxy) -5-methylbenzenesulf onyl) (benzenecarbonyl) -
diazomethane ,
( 2- (n-butyloxy) -5- tert -butylbenzenesulf onyl) (benzene-
carbonyl ) diazomethane ,
( 2- (n-pentyloxy ) -5- tert-butylbenzenesulf onyl) (benzene-
carbonyl ) diazomethane ,
( 2- (n-hexyloxy) -5- tert-butylbenzenesulf onyl) (benzene-
carbonyl ) diazomethane ,
( 2 - (n-butyloxy ) - 5 -methylbenzenesulf onyl ) ( 2 - naphthalene -
carbonyl ) diazomethane ,
( 2- (n-pentyloxy ) -5-methylbenzenesulf onyl) ( 2 -naphthalene -
carbonyl ) diazomethane ,
(2- (n-hexyloxy) -5-methylbenzenesulf onyl) ( 2 -naphthalene -
carbonyl ) diazomethane ,
( 2- (n-butyloxy) -5- tert -butylbenzenesulf onyl) ( 2 -naphthalene-
carbonyl ) diazomethane ,
(2- (n-pentyloxy) -5- tert-butylbenzenesulf onyl) ( 2-naphthalene-
carbonyl ) diazomethane ,
( 2- (n-hexyloxy) -5- tert-butylbenzenesulf onyl ) ( 2 -naphthalene -
carbonyl ) diazomethane , etc .
In the chemical amplification resist composition, an
appropriate amount of the sulf onyldiazomethane compound of
formula (1) or (la) added is from more than 0 part to 10
parts by weight, and preferably from 1 to 5 parts by weight,
per 100 parts by weight of the solids in the composition.
The sulf onyldiazomethane compound is used at least in an
amount to generate a sufficient amount of acid to deblock
5 acid labile groups in the polymer. Too large amounts may
excessively reduce the transmittance of resist film, failing
to form a rectangular pattern, and give rise to problems of
abnormal particles and deposits during resist storage. The
photoacid generators may be used alone or in admixture of two
10 or more.
Component (C)
In one preferred embodiment, the resist composition
further contains (C) a compound capable of generating an acid
15 upon exposure to high energy radiation, that is, a second
photoacid generator other than the sulf onyldiazomethane (B)
having formula (1) or (la). Suitable second photoacid
generators include sulfonium salts, iodonium salts,
sulf onyldiazomethane and N-sulf onyloxyimide photoacid
20 generators . Exemplary second photoacid generators are given
below while they may be used alone or in admixture of two or
more .
Sulfonium salts are salts of sulfonium cations with
sulfonates. Exemplary sulfonium cations include
25 triphenylsulf onium , ( 4 - t ert - but oxyphenyl ) diphenylsulf onium ,
bis ( 4 - tert -butoxyphenyl ) phenylsulf onium ,
tris( 4 -tert -butoxyphenyl) sulfonium,
( 3 - tert - but oxyphenyl ) diphenylsulf onium ,
bis ( 3 - tert -but oxyphenyl ) phenylsulf onium ,
30 tris ( 3 - tert -butoxyphenyl ) sulfonium ,
( 3 , 4 -di- tert -butoxyphenyl ) diphenylsulf onium,
bis ( 3 , 4 - di - tert -but oxyphenyl ) phenylsulf onium ,
tris ( 3 , 4-di- tert -butoxyphenyl) sulf onium,
diphenyl ( 4 - thiophenoxyphenyl ) sulfonium,
35 ( 4 - tert -butoxycarbonylmethyloxyphenyl ) diphenylsulf onium ,
tris ( 4- tert -butoxycarbonylmethyloxyphenyl) sulf onium,
( 4 -tert -butoxyphenyl) bis ( 4 - dime thylaminophenyl) sulf onium.
-42-
tris ( 4-dimethylaminophenyl) sulf onium,
2-naphthyldiphenylsulf onium, dimethyl- 2 -naphthylsulf onium,
4-hydroxyphenyldimethylsulf onium,
4-methoxyphenyldimethylsulf onium, trimethylsulf onium,
5 2-oxocyclohexylcyclohexylmethylsulf onium,
trinaphthylsulf onium , tribenzylsulf onium ,
diphenylmethylsulf onium , dimethylphenylsulf onium , and
2 - oxo - 2 - phenylethylthiacyclopent anium . Exemplary sulfonates
include trif luoromethanesulf onate , nonaf luorobutanesulf onate ,
10 heptadecaf luorooctanesulf onate ,
2,2, 2 -trif luoroethanesulf onate , pentaf luorobenzenesulf onate ,
4-trif luoromethylbenzenesulf onate, 4-f luorobenzenesulf onate ,
mesitylenesulf onate, 2,4, 6- triisopropylbenzenesulf onate ,
toluenesulf onate , benzenesulf onate ,
15 4- ( 4 1 -toluenesulf onyloxy) benzenesulf onate ,
naphthalenesulf onate , camphorsulf onate , octanesulf onate ,
dodecylbenzenesulf onate , butanesulf onate , and
methanesulf onate . Sulf onium salts based on combination of
the foregoing examples are included.
20 Iodinium salts are salts of iodonium cations with
sulfonates . Exemplary iodinium cations are aryliodonium
cations including diphenyliodinium,
bis ( 4 - tert -butylphenyl ) iodonium ,
4 - tert -butoxyphenylphenyliodonium , and
25 4-methoxyphenylphenyliodonium. Exemplary sulfonates include
trif luoromethanesulf onate , nonaf luorobutanesulf onate ,
heptadecaf luorooctanesulf onate ,
2,2, 2 -trif luoroethanesulf onate , pentaf luorobenzenesulf onate ,
4-trif luoromethylbenzenesulf onate , 4-f luorobenzenesulf onate ,
30 mesitylenesulf onate , 2,4,6- triisopropylbenzenesulf onate ,
toluenesulf onate , benzenesulf onate ,
4- ( 4- toluenesulf onyloxy ) benzenesulf onate ,
naphthalenesulf onate , camphorsulf onate , octanesulf onate ,
dodecylbenzenesulf onate , butanesulf onate , and
35 methanesulf onate . Iodonium salts based on combination of the
foregoing examples are included.
-43-
Exemplary sulf onyldiazomethane compounds include
bissulf onyldiazomethane compounds and
sulf onyl-carbonyldiazomethane compounds such as
bis ( ethylsulf onyl ) diazomethane ,
bis ( 1 -methylpropylsulf onyl ) diazomethane ,
bis ( 2 -methylpropylsulf onyl ) diazomethane ,
bis ( 1 , 1 -dimethylethylsulf onyl ) diazomethane ,
bis ( cyclohexylsulf onyl ) diazomethane ,
bis ( perf luoroisopropylsulf onyl ) diazomethane ,
bis ( phenylsulf onyl ) diazomethane ,
bis ( 4 -methylphenylsulf onyl ) diazomethane ,
bis ( 2 , 4 - dimethylphenylsulf onyl ) diazomethane ,
bis ( 2 -naphthylsulf onyl ) diazomethane ,
bis ( 4 -acetyloxyphenylsulf onyl ) diazomethane ,
bis ( 4 -me thanesulf onyloxyphenylsulf onyl) diazomethane ,
bis ( 4 - ( 4 - toluenesulf onyloxy ) phenylsulf onyl ) diazomethane ,
4 -methylphenylsulf onylbenzoyldiazomethane ,
tert-butylcarbonyl- 4 -methylphenylsulf onyldiazomethane,
2 -naphthylsulf onylbenzoyldiazomethane ,
4 - methylphenylsulf onyl- 2 -naphthoyldiazomethane,
methylsulf onylbenzoyldiazomethane , and
tert -but oxycarbonyl- 4 -methylphenylsulf onyldiazomethane .
N-sulf onyloxyimide photoacid generators include
combinations of imide skeletons with sulfonates. Exemplary
imide skeletons are succinimide, naphthalene dicarboxylic
acid imide, phthalimide, cyclohexyldicarboxylic acid imide,
5 - norbornene-2 , 3 -dicarboxylic acid imide, and
7-oxabicyclo[ 2 ,2.1] -5-heptene-2 , 3 -dicarboxylic acid imide .
Exemplary sulfonates include trif luoromethanesulf onate ,
nonaf luorobutanesulf onate , heptadecaf luorooctanesulf onate ,
2,2, 2- trif luoroethanesulf onate , pentaf luorobenzenesulf onate ,
4- trif luoromethylbenzenesulf onate , 4-f luorobenzenesulf onate ,
mesitylenesulf onate, 2,4, 6- triisopropylbenzenesulf onate,
toluenesulf onate , benzenesulf onate , naphthalenesulf onate ,
camphorsulf onate , octanesulf onate , dodecylbenzenesulf onate ,
butanesulf onate , and methanesulf onate .
Benzoinsulf onate photoacid generators include benzoin
tosylate, benzoin mesylate, and benzoin butanesulf onate .
Pyrogallol trisulfonate photoacid generators include
pyrogallol, f luoroglycine , catechol, resorcinol, hydroquinone ,
5 in which all the hydroxyl groups are substituted with
trif luoromethanesulf onate , nonaf luorobutanesulf onate ,
heptadecaf luorooctanesulf onate ,
2,2, 2-trif luoroethanesulf onate, pentaf luorobenzenesulf onate,
4-trif luoromethylbenzenesulf onate , 4-f luorobenzenesulf onate,
10 toluenesulf onate , benzenesulf onate , naphthalenesulf onate ,
camphorsulf onate , octanesulf onate , dodecylbenzenesulf onate ,
butanesulf onate, and methanesulf onate .
Nitrobenzyl sulfonate photoacid generators include
2 , 4-dinitrobenzyl sulfonate, 2-nitrobenzyl sulfonate, and
15 2 , 6-dinitrobenzyl sulfonate, with exemplary sulfonates
including trif luoromethanesulf onate ,
nonaf luorobutanesulf onate , heptadecaf luorooctanesulf onate ,
2,2, 2-trif luoroethanesulf onate, pentaf luorobenzenesulf onate ,
4 - trif luoromethylbenzenesulf onate , 4 -f luorobenzenesulf onate ,
20 toluenesulf onate , benzenesulf onate , naphthalenesulf onate ,
camphorsulf onate , octanesulf onate , dodecylbenzenesulf onate ,
butanesulf onate, and methanesulf onate . Also useful are
analogous nitrobenzyl sulfonate compounds in which the nitro
group on the benzyl side is substituted with a
25 trif luoromethyl group.
Sulfone photoacid generators include
bis ( phenylsulf onyl ) methane ,
bis ( 4 -methylphenylsulf onyl) methane ,
bis ( 2 -naphthylsulf onyl) methane,
30 2 , 2 -bis (phenylsulf onyl) propane,
2 , 2 -bis ( 4 -methylphenylsulf onyl) propane,
2 , 2 -bis ( 2 -naphthylsulf onyl) propane ,
2 -methyl - 2 - ( p - toluenesulf onyl ) propiophenone ,
2 - cyclohexylcarbonyl - 2 - ( p - toluenesulf onyl ) propane , and
35 2 , 4 -dimethyl- 2- ( p- toluenesulf onyl) pentan- 3 -one.
-45-
Photoacid generators in the form of glyoxime
derivatives are described in Japanese Patent No. 2,906,999
and JP-A 9-301948 and include
bis -O- ( p - toluenesulf onyl ) - a- dimethylglyoxime ,
5 bis-O- (p- toluenesulf onyl) -a-diphenylglyoxime ,
bis -O- ( p - toluenesulf onyl ) - a- dicyclohexylglyoxime ,
bis-O- (p- toluenesulf onyl) -2 , 3-pentanedioneglyoxime ,
bis-O- (n-butanesulf onyl) -a- dimethylglyoxime ,
bis-O- (n-butanesulf onyl ) -a-diphenylglyoxime ,
10 bis-O- (n-butanesulf onyl) - a- dicyclohexylglyoxime ,
bis-O- (methanesulf onyl ) -a- dimethylglyoxime ,
bis-O- ( trif luoromethanesulf onyl) -a- dimethylglyoxime ,
bis-O- (2,2, 2 -trif luoroethanesulf onyl) -a- dimethylglyoxime,
bis-O- ( 10- camphor sulf onyl) - a- dimethylglyoxime ,
15 bis-O- (benzenesulf onyl) - a- dimethylglyoxime ,
bis-O- (p-f luorobenzenesulf onyl) -a- dimethylglyoxime,
bis-O- (p- trif luoromethylbenzenesulf onyl) -a- dimethylglyoxime ,
bis-O- (xylenesulf onyl) - a- dimethylglyoxime ,
bis -O- ( trif luoromethanesulf onyl ) -nioxime ,
20 bis-O- (2,2, 2-trif luoroethanesulf onyl) -nioxime,
bis-O- ( 10-camphorsulf onyl ) -nioxime ,
bis-O- (benzenesulf onyl) -nioxime,
bis-O- (p-f luorobenzenesulf onyl) -nioxime,
bis-O- (p- trif luoromethylbenzenesulf onyl) -nioxime , and
25 bis-O- (xylenesulf onyl) -nioxime.
Also included are the oxime sulfonates described in
USP 6,004,724, for example,
( 5 - ( 4 - toluenesulf onyl ) oxyimino - 5H- thiophen - 2 -ylidene ) phenyl -
acetonitrile ,
30 ( 5- ( 10-camphorsulf onyl)oxyimino-5H-thiophen-2-ylidene)phenyl-
acetonitrile ,
( 5 -n-octanesulf onyloxyimino - 5H- thiophen- 2 -ylidene ) phenyl -
acetonitrile ,
-46-
( 5 - ( 4 - toluenesulf onyl ) oxyimino - 5H- thiophen - 2 -ylidene ) ( 2 -
methylphenyl ) acetonitrile ,
( 5 - ( 1 0 - camphor sulf onyl ) oxyimino - 5H - thiophen - 2 -ylidene ) ( 2 -
methylphenyl ) acetonitrile ,
5 ( 5-n-octanesulf onyloxyimino-5H- thiophen -2 -ylidene) ( 2-methyl-
phenyl ) acetonitrile , etc .
Also included are the oxime sulfonates described in
USP 6,261,738 and JP-A 2000-314956, for example,
2,2, 2-trif luoro-l-phenyl-ethanone oxime-O-methylsulf onate;
10 2,2 , 2-trif luoro-l-phenyl-ethanone oxime-O- ( 10-camphoryl-
sulf onate ) ;
2,2, 2-trif luoro-l-phenyl-ethanone oxime-O- ( 4 -met hoxy phenyl -
sulfonate) ;
2,2, 2-trif luoro-l-phenyl-ethanone oxime-O- ( 1-naphthyl-
15 sulfonate) ;
2,2, 2-trif luoro-l-phenyl-ethanone oxime-O- ( 2-naphthyl-
sulf onate) ;
2 , 2 , 2-trif luoro-l-phenyl-ethanone oxime-O- (2,4, 6-trimethyl-
phenylsulf onate) ;
20 2,2, 2- trif luoro-1- ( 4 -methylphenyl ) -ethanone oxime-O- ( 10-
camphorylsulf onate) ;
2,2, 2-trif luoro-1- ( 4 -methylphenyl) -ethanone oxime-O- ( methyl -
sulf onate) ;
2 , 2 , 2-trif luoro-1- ( 2 -methylphenyl ) -ethanone oxime-O- ( 10-
25 camphorylsulf onate) ;
2 , 2 , 2-trif luoro-1- ( 2 , 4-dimethylphenyl) -ethanone oxime-O- (10-
camphorylsulf onate) ;
2,2, 2-trif luoro-1- ( 2 , 4-dimethylphenyl) -ethanone oxime-O- ( 1-
naphthylsulf onate) ;
30 2,2 , 2-trif luoro-1- ( 2 , 4-dimethylphenyl) -ethanone oxime-O- ( 2-
naphthylsulf onate) ;
2 , 2 , 2-trif luoro-1- ( 2,4, 6-trimethylphenyl) -ethanone oxime-O-
( 10-camphorylsulf onate ) ;
2 , 2 , 2-trif luoro-1- ( 2,4, 6-trimethylphenyl) -ethanone oxime-O-
35 ( 1-naphthylsulf onate) ;
2 , 2 , 2-trif luoro-1- (2,4, 6-trimethylphenyl) -ethanone oxime-O-
(2-naphthylsulfonate) ;
-47
2 , 2 , 2-trif luoro-1- ( 4-methoxyphenyl ) -ethanone oxime-O-methyl-
sulf onate;
2,2, 2-trif luoro-1- ( 4 -methylthiophenyl) -ethanone oxime-O-
methylsulf onate;
5 2,2, 2-trif luoro-1- ( 3 , 4 -dimethoxyphenyl ) -ethanone oxime-O-
methylsulf onate ;
2,2,3,3,4,4, 4-heptaf luoro- 1 -phenyl -butanone oxime-O- ( 10-
camphorylsulf onate) ;
2 , 2 , 2-trif luoro-1- (phenyl) -ethanone oxime-O-methylsulf onate;
10 2,2 , 2-trif luoro-1- (phenyl) -ethanone oxime-O- 10 -camphoryl-
sulf onate;
2,2, 2-trif luoro-1- (phenyl) -ethanone oxime-O- (4-methoxy-
phenyl ) sulfonate ;
2,2, 2-trif luoro-1- (phenyl) -ethanone oxime-O- ( 1-naphthyl) -
15 sulfonate;
2,2, 2-trif luoro-1- (phenyl) -ethanone oxime-O- ( 2-naphthyl) -
sulfonate;
2,2, 2-trif luoro- 1- ( phenyl ) -ethanone oxime-O- (2,4, 6-trimethyl-
phenyl ) sulfonate ;
20 2,2, 2-trif luoro-1- ( 4-methylphenyl ) -ethanone oxime-O- ( 10-
camphoryl ) sulfonate ;
2 , 2 , 2-trif luoro-1- ( 4-methylphenyl) -ethanone oxime-O-methyl-
sulf onate ;
2,2, 2-trif luoro-1- ( 2-methylphenyl) -ethanone oxime-O- ( 10-
25 camphoryl ) sulfonate ;
2,2, 2-trif luoro-1- ( 2 , 4-dimethylphenyl ) -ethanone oxime-O- ( 1-
naphthyl ) sulfonate ;
2,2, 2-trif luoro-1- ( 2 , 4-dimethylphenyl) -ethanone oxime-O- ( 2-
naphthyl ) sulfonate ;
30 2,2, 2-trif luoro-1- (2,4, 6 - trimethylphenyl ) -ethanone oxime-O-
( 10 - camphoryl ) sulfonate;
2,2, 2-trif luoro-1- (2,4, 6 -trimethylphenyl) -ethanone oxime-O-
( 1-naphthyl) sulfonate;
2,2, 2-trif luoro-1- (2,4, 6 -trimethylphenyl) -ethanone oxime-O-
35 ( 2-naphthyl) sulfonate;
2,2, 2-trif luoro-1- ( 4-methoxyphenyl) -ethanone oxime-O-
methylsulf onate ;
-48-
2 , 2 , 2-trif luoro-1- ( 4 -thiomethylphenyl) -ethanone oxime-O-
methylsulf onate ;
2 , 2 , 2-trif luoro-1- ( 3 , 4-dimethoxyphenyl) -ethanone oxime-O-
methylsulf onate ;
5 2,2, 2-trif luoro-1- ( 4 -methoxyphenyl) -ethanone oxime-O- ( 4-
methylphenyl ) sulfonate ;
2,2, 2-trif luoro-1- ( 4 -methoxyphenyl) -ethanone oxime-O- (4-
methoxyphenyl ) sulfonate ;
2,2, 2-trif luoro-1- ( 4 -methoxyphenyl ) -ethanone oxime-O- ( 4-
10 dodecylphenyl ) sulfonate ;
2,2, 2-trif luoro-1- ( 4 -methoxyphenyl) -ethanone oxime-O-
octylsulf onate ;
2,2, 2- trif luoro- 1- ( 4- thiomethylphenyl ) -ethanone oxime-O- ( 4-
methoxyphenyl ) sulfonate ;
15 2,2, 2- trif luoro-1- ( 4 -thiomethylphenyl) -ethanone oxime-O- ( 4-
dodecylphenyl ) sulfonate ;
2,2, 2- trif luoro- 1- ( 4- thiomethylphenyl) -ethanone oxime-O-
octylsulf onate ;
2,2, 2-trif luoro-1- ( 4- thiomethylphenyl) -ethanone oxime-O- ( 2-
20 naphthyl ) sulfonate ;
2,2, 2-trif luoro-1- ( 2 -methylphenyl ) -ethanone oxime-O-
methylsulf onate ;
2,2, 2-trif luoro-1- ( 4 -methylphenyl) -ethanone oxime-O-
phenylsulf onate ;
25 2,2 , 2-trif luoro-1- (4-chlorophenyl) -ethanone oxime-O-
phenylsulf onate ;
2,2,3,3,4,4, 4 -heptaf luoro-1- (phenyl) -butanone oxime-O- (10-
camphoryl ) sulfonate ;
2, 2 , 2-trif luoro- 1- naphthyl -ethanone oxime-O-methylsulf onate ;
30 2,2, 2- trif luoro- 2 -naphthyl -ethanone oxime-O-methylsulf onate ;
2,2, 2-trif luoro-1- [ 4-benzylphenyl] -ethanone oxime-O-methyl-
sulf onate;
2,2,2- trif luoro - 1 - [ 4 - ( phenyl -1,4- dioxa- but - 1 - yl ) phenyl ] -
ethanone oxime-O-methylsulf onate;
35 2,2, 2-trif luoro- 1-naphthyl-ethanone oxime-O-propylsulf onate;
2 , 2 , 2-trif luoro- 2-naphthyl-ethanone oxime-O-propylsulf onate ;
-49-
2 , 2 , 2-trif luoro-1- [ 4-benzylphenyl ] -ethanone oxime -O- propyl -
sulfonate;
2,2, 2-trif luoro-1- [ 4-methylsulf onylphenyl] -ethanone oxime -0
propylsulf onate ;
1 , 3 -bis [ 1- ( 4-phenoxyphenyl) -2 , 2 , 2-trif luoroethanone oxime -0
sulf onyl ] phenyl ;
2,2, 2-trif luoro-1- [ 4-methylsulf onyloxyphenyl] -ethanone
oxime-O-propylsulf onate ;
2,2, 2-trif luoro- 1- [ 4-methylcarbonyloxyphenyl] -ethanone
oxime-O-propylsulf onate;
2,2, 2-trif luoro-1- [ 6H, 7H-5, 8-dioxonaphth-2-yl] -ethanone
oxime-O-propylsulf onate ;
2,2, 2-trif luoro- 1- [ 4-methoxycarbonylmethoxyphenyl] -ethanone
oxime-O-propylsulf onate;
2,2, 2-trif luoro-1- [4- (methoxycarbonyl) - ( 4 -amino- 1 -oxa- pent -
yl) -phenyl] -ethanone oxime-O-propylsulf onate;
2,2, 2-trif luoro-1- [ 3 , 5 -dimethyl- 4 -ethoxyphenyl] -ethanone
oxime-O-propylsulf onate ;
2,2, 2-trif luoro-1- [ 4-benzyloxyphenyl] -ethanone oxime-O-
propylsulf onate ;
2,2, 2-trif luoro-1- [ 2- thiophenyl ] -ethanone oxime-O-
propylsulf onate ; and
2,2, 2-trif luoro-1- [ l-dioxa-thiophen-2-yl) ] -ethanone oxime -O
propylsulf onate .
Also included are the oxime sulfonates described in
JP-A 9-95479 and JP-A 9-230588 and the references cited
therein, for example,
a- (p-toluenesulf onyloxyimino) -phenylacetonitrile ,
a- (p-chlorobenzenesulf onyloxyimino ) -phenylacetonitrile,
a- ( 4 -nitrobenzenesulf onyloxyimino ) -phenylacetonitrile ,
a- ( 4-nitro-2-trif luoromethylbenzenesulf onyloxyimino) -
phenylacetonitrile ,
a- ( benzenesulf onyloxyimino ) - 4 -chlorophenylacetonitrile ,
a- (benzenesulf onyloxyimino) -2 , 4-dichlorophenylacetonitrile ,
a- (benzenesulf onyloxyimino) -2 , 6-dichlorophenylacetonitrile ,
-50-
a- (benzenesulf onyloxyimino) -4-methoxyphenylacetonitrile,
a- ( 2 - chlorobenzenesulf onyloxyimino ) - 4 -methoxyphenylacet o -
nitrile,
a- (benzenesulf onyloxyimino) -2-thienylacetonitrile,
a- ( 4 -dodecylbenzenesulf onyloxyimino) -phenylacetonitrile ,
a- [ ( 4- toluenesulf onyloxyimino) -4-methoxyphenyl]acetonitrile,
a- [ (dodecylbenzenesulf onyloxyimino) -4-methoxyphenyl] aceto-
nitrile,
a- ( tosyloxyimino ) - 3 - thienylacetonitrile ,
a- ( me thylsulf onyloxyimino ) - 1 - cyclopentenylacetonitrile ,
a- ( ethylsulf onyloxyimino ) - 1 - cyclopentenylacetonitrile ,
a- (isopropylsulf onyloxyimino) -1-cyclopentenylacetonitrile,
a- ( n-butylsulf onyloxyimino ) - 1-cyclopentenylacetonitrile ,
a- (ethylsulf onyloxyimino) -1-cyclohexenylacetonitrile,
a- (isopropylsulf onyloxyimino) -1-cyclohexenylacetonitrile, and
a- (n-butylsulf onyloxyimino) -1-cyclohexenylacetonitrile.
Suitable bisoxime sulfonates include those described
in JP-A 9-208554, for example,
bis (a- ( 4- toluenesulf onyloxy) imino) -p-phenylenediacetonitrile ,
bis ( a- ( benzenesulf onyloxy ) imino ) -p-phenylenediacetonitrile ,
bis (a- (methanesulf onyloxy) imino) -p-phenylenediacetonitrile,
bis ( a- ( butanesulf onyloxy ) imino ) -p-phenylenediacetonitrile ,
bis (a- ( 10-camphorsulf onyloxy) imino) -p-phenylenediaceto-
nitrile ,
bis (a- ( 4- toluenesulf onyloxy) imino) -p-phenylenediacetonitrile,
bis ( a- ( trif luoromethanesulf onyloxy ) imino ) -p-phenylenediaceto-
nitrile,
bis (a- ( 4 -methoxybenzenesulf onyloxy) imino) -p-phenylenediaceto-
nitrile,
bis ( a- ( 4 -toluenesulf onyloxy ) imino ) -m-phenylenediacetonitrile ,
bis ( a- ( benzenesulf onyloxy ) imino ) -m-phenylenediacetonitrile ,
bis ( a- ( methanesulf onyloxy ) imino ) -m-phenylenediacetonitrile ,
bis ( a- ( butanesulf onyloxy ) imino ) -m-phenylenediacetonitrile ,
bis (a- ( 10 -camphorsulf onyloxy) imino) -m-phenylenediaceto-
nitrile,
bis ( a- ( 4 - toluenesulf onyloxy ) imino ) -m-phenylenediacetonitrile ,
bis ( a- ( trif luoromethanesulf onyloxy ) imino ) -m-phenylenediaceto-
nitrile,
bis ( a- ( 4 -methoxybenzenesulf onyloxy ) imino ) -m-phenylenediaceto-
nitrile, etc.
Of these, preferred photoacid generators are sulfonium
salts , bissulf onyldiazomethanes , N-sulf onyloxyimides and
glyoxime derivatives. More preferred photoacid generators
are sulfonium salts, bissulf onyldiazomethanes , and
N-sulf onyloxyimides . Typical examples include
triphenylsulf onium p- toluenesulf onate ,
triphenylsulf onium camphorsulf onate ,
triphenylsulf onium pentaf luorobenzenesulf onate ,
triphenylsulf onium nonaf luorobutanesulf onate ,
triphenylsulf onium 4- ( 4 1 -toluenesulf onyloxy )benzenesulf onate,
triphenylsulf onium 2,4,6- triisopropylbenzenesulf onate ,
4 - tert -butoxyphenyldiphenylsulf onium p - toluenesulf onate ,
4- tert-butoxyphenyldiphenylsulf onium camphorsulf onate ,
4- tert-butoxyphenyldiphenylsulf onium 4- (4 1 -toluenesulf onyl-
oxy )benzenesulf onate ,
tris ( 4 -methylphenyl ) sulfonium camphorsulf onate ,
tris ( 4 - tert-butylphenyl ) sulfonium camphorsulf onate ,
bis ( tert-butylsulf onyl ) diazomethane ,
bis ( cyclohexylsulf onyl ) diazomethane ,
bis ( 2 , 4 -dime thy lphenylsulf onyl) diazomethane,
bis ( 4 - tert -butylphenylsulf onyl ) diazomethane ,
N-camphorsulf onyloxy- 5-norbornene- 2 , 3-carboxylic acid imide,
and N-p-toluenesulf onyloxy - 5 - norbornene - 2 , 3-carboxylic acid
imide .
In the resist composition comprising the
sulf onyldiazomethane of formula (1) or (la) as the first
photoacid generator according to the invention, the second
-52-
photoacid generator (C) may be used in any desired amount as
long as it does not compromise the effects of the
sulf onyldiazomethane of formula (1) or (la). An appropriate
amount of the second photoacid generator (C) is 0 to 10
5 parts, and especially 0 to 5 parts by weight per 100 parts by
weight of the solids in the composition. Too high a
proportion of the second photoacid generator (C) may give
rise to problems of degraded resolution and foreign matter
upon development and resist film peeling. The second
10 photoacid generators may be used alone or in admixture of two
or more. The transmittance of the resist film can be
controlled by using a (second) photoacid generator having a
low transmittance at the exposure wavelength and adjusting
the amount of the photoacid generator added.
15 In the resist composition comprising the
sulf onyldiazomethane as the photoacid generator according to
the invention, there may be added a compound which is
decomposed with an acid to generate an acid, that is,
acid-propagating compound. For these compounds, reference
20 should be made to J. Photopolym. Sci. and Tech., 8, 43-44,
45-46 (1995), and ibid., 9, 29-30 (1996).
Examples of the acid-propagating compound include
tert -butyl- 2 -methyl- 2 - tosyloxymethyl acetoacetate and
2-phenyl-2- ( 2- tosyloxyethyl ) -1 , 3-dioxolane, but are not
25 limited thereto. Of well-known photoacid generators, many of
those compounds having poor stability, especially poor
thermal stability exhibit an acid-propagating compound-like
behavior .
In the resist composition comprising the
30 sulf onyldiazomethane as the photoacid generator according to
the invention, an appropriate amount of the acid-propagating
compound is up to 2 parts, and especially up to 1 part by
weight per 100 parts by weight of the solids in the
composition. Excessive amounts of the acid-propagating
35 compound make diffusion control difficult, leading to
degradation of resolution and pattern configuration.
-53-
Component ( D )
The basic compound used as component (D) is preferably
a compound capable of suppressing the rate of diffusion when
the acid generated by the photoacid generator diffuses within
the resist film. The inclusion of this type of basic
compound holds down the rate of acid diffusion within the
resist film, resulting in better resolution. In addition, it
suppresses changes in sensitivity following exposure and
reduces substrate and environment dependence, as well as
improving the exposure latitude and the pattern profile.
Examples of basic compounds include primary, secondary,
and tertiary aliphatic amines, mixed amines, aromatic amines,
heterocyclic amines, carboxyl group-bearing nitrogenous
compounds, sulfonyl group-bearing nitrogenous compounds,
hydroxyl group-bearing nitrogenous compounds, hydroxyphenyl
group-bearing nitrogenous compounds, alcoholic nitrogenous
compounds, amide derivatives, and imide derivatives.
Examples of suitable primary aliphatic amines include
ammonia, methylamine, ethylamine, n - propylamine ,
isopropylamine , n-butylamine , isobutylamine , sec-butylamine ,
tert-butylamine, pentylamine, tert-amylamine ,
cyclopentylamine , hexylamine , cyclohexylamine , heptylamine ,
octylamine, nonylamine, decylamine, dodecylamine, cetylamine,
methylenediamine , ethylenediamine , and tetraethylenepentamine .
Examples of suitable secondary aliphatic amines include
dimethylamine , diethylamine , di-n-propylamine ,
diisopropylamine , di-n-butylamine , diisobutylamine ,
di-sec-butylamine , dipentylamine , dicyclopentylamine ,
dihexylamine , dicyclohexylamine , diheptylamine , dioctylamine ,
dinonylamine , didecylamine , didodecylamine , dicetylamine ,
N , N - dimethylmethylenediamine , N , N- dime thylethylenediamine ,
and N,N-dimethyltetraethylenepentamine . Examples of suitable
tertiary aliphatic amines include trimethylamine,
triethylamine , tri-n-propylamine , triisopropylamine ,
tri-n-butylamine , triisobutylamine , tri-sec-butylamine ,
tripentylamine , tricyclopentylamine , trihexylamine ,
tricyclohexylamine , triheptylamine , trioctylamine ,
-54-
trinonylamine , tridecylamine , tridodecylamine , tricetylamine ,
N,N,N' , N" -tetramethylmethylenediamine ,
N , N , N ' , N ' - t e tramethyle thylenediamine , and
N,N,N' , N' - tetramethyltetraethylenepent amine .
Examples of suitable mixed amines include
dimethylethylamine , methylethylpropylamine , benzylamine ,
phenethylamine , and benzyldimethylamine . Examples of
suitable aromatic and heterocyclic amines include aniline
derivatives (e.g., aniline, N-methylaniline , N-ethylaniline,
N-propylaniline , N , N-dimethylaniline , 2 -methylaniline ,
3 - methylaniline , 4 -methylaniline , ethylaniline , propylaniline ,
trimethylaniline , 2 -nitroaniline , 3 -nitroaniline ,
4- nitroaniline , 2 , 4-dinitroaniline, 2 , 6-dinitroaniline,
3 , 5-dinitroaniline , and N,N-dimethyltoluidine) ,
diphenyl ( p- tolyl ) amine , methyldiphenylamine , triphenylamine ,
phenylenediamine , naphthylamine , diaminonaphthalene ,
pyrrole derivatives (e.g., pyrrole, 2H-pyrrole,
1 - methylpyrrole , 2,4- dimethylpyrrole , 2,5- dimethylpyrrole #
and N-methylpyrrole ) , oxazole derivatives (e.g., oxazole and
isooxazole) , thiazole derivatives (e.g., thiazole and
isothiazole) , imidazole derivatives (e.g., imidazole,
4-methylimidazole , and 4-methyl-2-phenylimidazole) ,
pyrazole derivatives , f urazan derivatives ,
pyrroline derivatives (e.g., pyrroline and
2 - methyl- 1 -pyrroline ) , pyrrolidine derivatives (e.g.,
pyrrolidine , N-methylpyrrolidine , pyrrolidinone , and
N-methylpyrrolidone) , imidazoline derivatives, imidazolidine
derivatives, pyridine derivatives (e.g., pyridine,
methylpyridine , ethylpyridine , propylpyridine , butylpyridine ,
4 - ( 1 - butylpen tyl ) pyridine , dime thy lpyridine ,
trimethylpyridine , triethylpyridine , pheny lpyridine ,
3 - methyl- 2 -phenylpyridine , 4 - tert - butylpyridine ,
diphenylpyridine , benzylpyridine , methoxypyridine ,
butoxypyridine , dimethoxypyridine , 1 -methyl- 2 -pyridone ,
4 - pyrrolidinopyridine , 1 -methyl- 4 -phenylpyridine ,
2- ( 1-ethylpropyl) pyridine, aminopyridine , and
dimethylaminopyridine) , pyridazine derivatives,
-55-
pyrimidine derivatives, pyrazine derivatives,
pyrazoline derivatives , pyrazolidine derivatives ,
piperidine derivatives, piperazine derivatives,
morpholine derivatives , indole derivatives ,
5 isoindole derivatives, lH-indazole derivatives,
indoline derivatives, quinoline derivatives (e.g., quinoline
and 3-quinolinecarbonitrile) , isoquinoline derivatives,
cinnoline derivatives, quinazoline derivatives,
quinoxaline derivatives, phthalazine derivatives,
10 purine derivatives, pteridine derivatives,
carbazole derivatives, phenanthridine derivatives,
acridine derivatives, phenazine derivatives,
1 , 10-phenanthroline derivatives, adenine derivatives,
adenosine derivatives, guanine derivatives,
15 guanosine derivatives, uracil derivatives, and
uridine derivatives .
Examples of suitable carboxyl group-bearing
nitrogenous compounds include aminobenzoic acid,
indolecarboxylic acid, and amino acid derivatives (e.g.
20 nicotinic acid, alanine, alginine, aspartic acid,
glutamic acid, glycine, histidine, isoleucine, glycylleucine,
leucine, methionine, phenylalanine, threonine, lysine,
3- aminopyrazine-2-carboxylic acid, and methoxyalanine ) .
Examples of suitable sulfonyl group-bearing nitrogenous
25 compounds include 3-pyridinesulf onic acid and pyridinium
p- toluenesulf onate . Examples of suitable hydroxyl
group-bearing nitrogenous compounds, hydroxyphenyl
group-bearing nitrogenous compounds, and alcoholic
nitrogenous compounds include 2-hydroxypyridine, aminocresol,
30 2 , 4-quinolinediol, 3-indolemethanol hydrate, monoethanolamine ,
diethanolamine , tr iethanolamine , N- ethyldie thanolamine ,
N,N-diethylethanolamine , triisopropanolamine ,
2,2' -iminodiethanol , 2-aminoethanol , 3-amino-l-propanol ,
4- amino-l-butanol, 4- ( 2 -hydroxyethyl) morpholine,
35 2 - ( 2 -hydroxyethyl ) pyridine , 1 - ( 2 -hydroxyethyl ) piperazine ,
1- [2- ( 2 -hydroxyethoxy) ethyl] piperazine, piperidine ethanol,
1 - ( 2 -hydroxyethyl ) pyrrolidine ,
-56-
1 - ( 2 -hydroxyethyl ) - 2 -pyrrolidinone ,
3-piperidino-l , 2 -propanediol , 3-pyrrolidino- 1 , 2 -propanediol,
8 -hydroxy julolidine , 3 - quinuclidinol , 3 - tropanol ,
1 -methyl -2 -pyrrolidine ethanol, 1-aziridine ethanol,
5 N- ( 2 -hydroxyethyl Jphthalimide , and
N- ( 2 -hydroxyethyl ) isonicotinamide . Examples of suitable
amide derivatives include formamide, N-methylf ormamide ,
N , N- dimethylf ormamide , acetamide , N-methylacetamide ,
N,N-dimethylacetamide, propionamide , and benzamide. Suitable
10 imide derivatives include phthalimide, succinimide, and
maleimide .
In addition, basic compounds of the following general
formula (Dl) may also be included alone or in admixture.
15 N(X') W (Y) 3 _ W (Dl)
In the formula, w is equal to 1, 2 or 3; Y is
independently hydrogen or a straight, branched or cyclic
alkyl group of 1 to 20 carbon atoms which may contain a
20 hydroxyl group or ether structure; and X 1 is independently
selected from groups of the following general formulas (X'l)
to (X'3), and two or three X' may bond together to form a
ring.
— R 300 — O— R 301 (X'l)
O
— R 302 — O— R 303 -^L_R 304 (x , 2)
O
_ R 305 L_Q_ R 306 (X3)
25 In the formulas, R 300 , R 302 and R 305 are independently
straight or branched alkylene groups of 1 to 4 carbon atoms;
R 301 , R 304 and R 306 are independently hydrogen, straight,
branched or cyclic alkyl groups of 1 to 20 carbon atoms,
which may contain at least one hydroxyl group, ether
30 structure, ester structure or lactone ring; and R 303 is a
single bond or a straight or branched alkylene group of 1 to
4 carbon atoms .
-57-
Illustrative examples of the basic compounds of
formula (Dl) include tris ( 2 -methoxymethoxyethyl) amine,
tris { 2 - ( 2 -methoxyethoxy ) ethyl } amine ,
tris{2- ( 2-methoxyethoxymethoxy)ethyl}amine ,
tris{2- ( 1 -methoxyethoxy ) ethyl >amine ,
tris{2- ( 1-ethoxyethoxy) ethyl} amine,
tris{2- ( 1-ethoxypropoxy ) ethyl} amine ,
tris [ 2 - { 2 - ( 2 -hydroxyethoxy ) ethoxy }ethyl ] amine ,
4,7,13,16,21,24 -hexaoxa -1,10- diazabicyclo [8.8.8] hexacosane ,
4,7,13, 18-tetraoxa- 1 , 10 -diazabicyclo [8 . 5 . 5 ]eicosane,
1,4,10, 13-tetraoxa-7 , 16-diazabicyclooctadecane ,
1-aza- 12-crown-4 , l-aza-15-crown-5 , l-aza-18-crown-6 ,
tris ( 2 - formyloxy ethyl ) amine , tris ( 2 - acetoxyethyl ) amine ,
tris ( 2 -propionyloxyethyl ) amine , tris ( 2 -butyryloxyethyl ) amine ,
tris ( 2 - isobutyryloxyethyl ) amine , tris ( 2 - valeryloxyethyl ) amine ,
tris ( 2 -pivaloyloxyethyl ) amine ,
N , N-bis ( 2 - acetoxyethyl ) - 2 - ( acetoxyacetoxy ) ethylamine ,
tris ( 2 -methoxycarbonyloxyethyl ) amine ,
tris ( 2 - t ert -butoxycarbonyloxyethyl ) amine ,
tris 1 2 - ( 2 - oxopropoxy ) ethyl ] amine ,
tris [2- (methoxycarbonylmethyl)oxyethyl] amine,
tris [ 2 - ( t ert -but oxycarbonylmethyloxy) ethyl ] amine ,
tris [ 2 - ( cyclohexyloxycarbonylmethyloxy ) ethyl ] amine ,
tris ( 2 -methoxycarbonylethyl ) amine ,
tris ( 2 - ethoxycarbonylethyl ) amine ,
N, N-bis ( 2-hydroxyethyl ) -2- (methoxycarbonyl) ethylamine,
N, N-bis ( 2 -acetoxyethyl ) -2- (methoxycarbonyl ) ethylamine,
N, N-bis ( 2-hydroxyethyl ) -2- ( ethoxycarbonyl) ethylamine ,
N , N-bis ( 2 - acetoxyethyl ) - 2 - ( ethoxycarbonyl ) ethylamine ,
N , N-bis ( 2-hydroxyethyl ) - 2 - ( 2 -methoxyethoxycarbonyl ) ethylamine ,
N, N-bis ( 2 -acetoxyethyl ) -2- ( 2 -methoxyethoxycarbonyl ) ethylamine ,
N , N-bis ( 2 - hydroxyethyl ) - 2 - ( 2 -hydroxyethoxycarbonyl ) ethylamine ,
N , N-bis ( 2 - acetoxyethyl ) - 2 - ( 2 - acetoxyethoxycarbonyl ) ethylamine ,
N, N-bis ( 2-hydroxyethyl) -2- [ (methoxycarbonyl) methoxycarbonyl] -
ethylamine ,
N, N-bis ( 2 -acetoxyethyl) -2- [ (methoxycarbonyl) methoxycarbonyl] -
ethylamine ,
-58-
N,N-bis ( 2 -hydroxyethyl) -2- ( 2 -oxopropoxycarbonyl) ethylamine,
N, N-bis ( 2-acetoxyethyl) -2- ( 2 -oxopropoxycarbonyl) ethylamine,
N , N-bis ( 2 -hydroxyethyl ) - 2 - ( tetrahydrof urf uryloxycarbonyl ) -
ethylamine ,
N /N-bis ( 2-acetoxyethyl) -2- ( tetrahydrof urf uryloxycarbonyl) -
ethylamine ,
N, N-bis ( 2 -hydroxyethyl) -2- [ ( 2-oxotetrahydrof uran-3-yl)oxy-
carbonyl ] ethylamine ,
N, N-bis ( 2-acetoxyethyl) -2- [ ( 2-oxotetrahydrofuran-3-yl)oxy-
carbonyl ] ethylamine ,
N, N-bis ( 2 -hydroxyethyl) -2- ( 4 -hydroxybutoxycarbonyl) ethylamine,
N, N-bis ( 2-f ormyloxyethyl) -2- ( 4-f ormyloxybutoxycarbonyl) -
ethylamine,
N, N-bis ( 2-f ormyloxyethyl) -2- ( 2-f ormyloxyethoxycarbonyl) -
ethylamine ,
N, N-bis ( 2-methoxyethyl) -2- (methoxycarbonyl) ethylamine,
N- ( 2 -hydroxyethyl ) -bis [ 2 - ( methoxycarbonyl ) ethyl ] amine ,
N- ( 2 - acetoxyethyl ) -bis [ 2 - ( methoxycarbonyl ) ethyl ] amine ,
N- ( 2 -hydroxyethyl ) -bis [ 2 - ( ethoxycarbonyl ) ethyl ] amine ,
N- ( 2-acetoxyethyl ) -bis [ 2 - ( ethoxycarbonyl ) ethyl ] amine ,
N- ( 3 -hydroxy- 1 -propyl ) -bis [ 2 - ( methoxycarbonyl ) ethyl ] amine ,
N- (3 -acetoxy-1 -propyl) -bis [ 2- (methoxycarbonyl) ethyl] amine,
N- ( 2 -methoxyethyl ) -bis [ 2 - ( methoxycarbonyl ) ethyl ] amine ,
N- butyl - bis [ 2 - ( methoxycarbonyl ) ethyl ] amine ,
N-butyl -bis [ 2 - ( 2 -methoxyethoxycarbonyl ) ethyl ] amine ,
N-methyl-bis ( 2-acetoxyethyl ) amine ,
N-ethyl-bis (2-acetoxyethyl ) amine ,
N-methyl-bis ( 2-pivaloyloxyethyl)amine,
N-ethyl-bis [2- (methoxycarbonyloxy) ethyl] amine,
N-ethyl-bis [ 2 - ( tert -butoxycarbonyloxy ) ethyl ] amine ,
tris ( methoxycarbonylmethyl ) amine ,
tris ( ethoxycarbonylmethyl ) amine ,
N-butyl -bis (methoxycarbonylmethyl) amine,
N-hexyl- bis (methoxycarbonylmethyl ) amine , and
(3- ( diethylamino ) -5-valerolactone .
-59-
Also useful are one or more of cyclic
structure-bearing basic compounds having the following
general formula (D2).
Herein X 1 is as defined above, and R 307 is a straight or
branched alkylene group of 2 to 20 carbon atoms which may
contain one or more carbonyl groups, ether structures, ester
structures or sulfide structures.
Illustrative examples of the cyclic structure-bearing
basic compounds having formula (D2) include
1- [2- (methoxymethoxy) ethyl] pyrrolidine,
1 - [ 2 - ( methoxymethoxy ) ethyl ] piper idine ,
4 - [ 2 - ( methoxymethoxy ) ethyl ] morpholine ,
1- [2- [ ( 2 -methoxyethoxy )methoxy] ethyl] pyrrolidine,
1 - [ 2 - [ ( 2 -methoxyethoxy ) methoxy ] ethyl ] piperidine ,
4- [2- [ (2 -methoxyethoxy) methoxy] ethyl] morpholine,
2- ( 1-pyrrolidinyl) ethyl acetate, 2-piperidinoethyl acetate,
2-morpholinoethyl acetate, 2- ( 1-pyrrolidinyl) ethyl formate,
2-piperidinoethyl propionate,
2 -morpholinoethyl acet oxyacet at e ,
2 - ( 1-pyrrolidinyl ) ethyl methoxyacetate ,
4 - [ 2 - ( methoxycarbonyloxy ) ethyl ] morpholine ,
1 - [ 2 - ( t -butoxycarbonyloxy ) ethyl ] piperidine ,
4 - [ 2 - ( 2 -methoxyethoxycarbonyloxy ) ethyl ] morpholine ,
methyl 3- ( 1-pyrrolidinyl) propionate,
methyl 3 -piperidinopropionate , methyl 3 -morpholinopropionate ,
methyl 3 - ( thiomorpholino ) propionate ,
methyl 2 -methyl- 3- ( 1-pyrrolidinyl) propionate,
ethyl 3 -morpholinopropionate ,
methoxycarbonylmethyl 3 -piperidinopropionate ,
2 - hydroxy ethyl 3- ( 1-pyrrolidinyl) propionate,
2-acetoxyethyl 3 -morpholinopropionate ,
2 - oxotetrahydrof uran - 3 -yl 3 - ( 1-pyrrolidinyl ) propionate ,
(D2)
-60-
tetrahydrof urf uryl 3 -morpholinopropionat e ,
glycidyl 3 -piperidinopropionate ,
2 -methoxyethyl 3 -morpholinopropionate ,
2 - ( 2 -methoxyethoxy ) ethyl 3 - ( 1 -pyrrolidinyl ) propionate ,
butyl 3 -morpholinopropionat e ,
cyclohexyl 3 -piperidinopropionate ,
a- ( 1 -pyrrolidinyl ) methyl -y-butyrolactone ,
p-piperidino-y-butyrolactone , |3-morpholino-S-valerolactone ,
methyl 1-pyrrolidinylacetate , methyl piperidinoacetate ,
methyl morpholinoacetate , methyl thiomorpholinoacetate ,
ethyl 1-pyrrolidinylacetate, and
2 -methoxyethyl morpholinoacetate .
Also, one or more of cyano-bearing basic compounds
having the following general formulae (D3) to (D6) may be
blended.
(X') 3 _w-N- (R 308 - CN) W (D3)
R 307 N R 308_ CN (D4)
o
(X') 3 _ w -N- ( R 308 J_ R 309_ ^ (D5)
R 307 N _ R 308^L R 309_ CN (D6)
Herein, X 1 , R 307 and w are as defined above, and R 308 and R 309
are each independently a straight or branched alkylene group
of 1 to 4 carbon atoms.
Illustrative examples of the cyano-bearing basic
compounds having formulae (D3) to (D6) include
3 - ( diethylamino ) propiononit rile ,
N , N-bis ( 2 -hydroxy ethyl ) - 3 -aminopropiononitrile ,
N , N-bis ( 2 -acetoxyethyl ) - 3 -aminopropiononitrile ,
N , N-bis ( 2 -f ormyloxyethyl ) - 3 - aminopropiononitrile ,
-61-
N , N-bis ( 2 -methoxyethyl ) - 3 -aminopropiononitrile ,
N , N- bis [ 2 - ( methoxyme thoxy ) ethyl ] - 3 - aminopropiononitrile ,
methyl N- ( 2-cyanoethyl) -N- ( 2 -methoxyethyl) -3-aminopropionate ,
methyl N- ( 2-cyanoethyl ) -N- ( 2 -hydroxy ethyl) -3-aminopropionate,
methyl N- ( 2-acetoxyethyl ) -N- (2-cyanoethyl) -3-aminopropionate,
N- (2-cyanoethyl) -N-ethyl- 3 -aminopropiononitrile ,
N- (2-cyanoethyl) -N- ( 2-hydroxyethyl) - 3 -aminopropiononitrile ,
N- (2-acetoxyethyl) -N- ( 2-cyanoethyl ) -3 -aminopropiononitrile ,
N- (2-cyanoethyl) -N- ( 2-f ormyloxyethyl) -3 -aminopropiononitrile,
N- (2-cyanoethyl) -N- ( 2 -methoxyethyl ) - 3 -aminopropiononitrile ,
N- (2-cyanoethyl) -N- [2- (methoxymethoxy) ethyl] -3 -aminopropiono-
nitrile ,
N- ( 2-cyanoethyl) -N- ( 3 -hydroxy- 1- propyl) -3 -aminopropiono-
nitrile ,
N- ( 3 -acetoxy-1 -propyl) -N- ( 2-cyanoethyl) -3 -aminopropiono-
nitrile,
N- ( 2-cyanoethyl) -N- ( 3 -formyloxy- 1 -propyl) -3-aminopropiono-
nitrile ,
N- (2- cyanoethyl ) -N- tetrahydrof urf uryl- 3 - aminopropiononitrile ,
N,N-bis(2- cyanoethyl ) - 3 - aminopropiononitrile ,
diethylaminoacetonitrile ,
N , N-bis ( 2-hydroxyethyl ) aminoacetonitrile ,
N , N-bis ( 2-acetoxyethyl ) aminoacetonitrile ,
N , N-bis ( 2 - f ormyloxyethyl ) aminoacetonitrile ,
N , N-bis ( 2 -methoxyethyl ) aminoacetonitrile ,
N , N-bis [ 2 - ( methoxymethoxy ) ethyl ] aminoacetonitrile ,
methyl N-cyanomethyl-N- ( 2 -methoxyethyl) -3-aminopropionate,
methyl N-cyanomethyl-N- ( 2-hydroxyethyl) -3-aminopropionate,
methyl N- ( 2-acetoxyethyl ) -N-cyanomethyl- 3-aminopropionate,
N-cyanomethyl-N- ( 2-hydroxyethyl) aminoacetonitrile,
N- ( 2-acetoxyethyl ) -N- ( cyanomethyl ) aminoacetonitrile ,
N-cyanomethyl-N- ( 2 - formyloxy ethyl ) aminoacetonitrile ,
N-cyanomethyl-N- ( 2 -methoxyethyl ) aminoacetonitrile ,
N-cyanomethyl-N- [ 2 - ( methoxymethoxy ) ethyl ) aminoacetonitrile ,
N-cyanomethyl-N- ( 3 -hydroxy- 1 -propyl ) aminoacetonitrile ,
N- ( 3 -acetoxy- 1 -propyl ) -N- ( cyanomethyl ) aminoacetonitrile ,
N-cyanomethyl-N- ( 3 -formyloxy- 1 -propyl ) aminoacetonitrile ,
-62-
N , N-bis ( cyanomethyl ) aminoacetonitrile ,
1 -pyrrolidinepropiononitrile , 1 -piperidinepropiononitrile ,
4 -morpholinepropiononitrile , 1 -pyrrolidineacetonitrile ,
1 - piperidineacetonitrile , 4 -morpholineacetonitrile ,
cyanomethyl 3-diethylaminopropionate ,
cyanomethyl N, N-bis ( 2 -hydroxy ethyl) -3-aminopropionate ,
cyanomethyl N,N-bis( 2-acetoxyethyl) -3-aminopropionate ,
cyanomethyl N,N-bis( 2-f ormyloxyethyl) -3-aminopropionate,
cyanomethyl N , N-bis ( 2 -methoxyethyl ) - 3-aminopropionate ,
cyanomethyl N, N-bis [2- (methoxymethoxy) ethyl] -3-amino-
propionate,
2 - cyanoe thyl 3 - die thylaminopropionat e ,
2 -cyanoethyl N , N-bis ( 2 -hydroxyethyl ) - 3 - aminopropionate ,
2-cyanoethyl N,N-bis( 2-acetoxyethyl) -3-aminopropionate,
2-cyanoethyl N, N-bis ( 2-f ormyloxyethyl) -3-aminopropionate,
2-cyanoethyl N, N-bis ( 2 -methoxyethyl) -3 -aminopropionate,
2-cyanoethyl N, N-bis [2- (methoxymethoxy ) ethyl] -3-amino-
propionate,
cyanomethyl 1 -pyrrolidinepropionate ,
cyanomethyl 1 -piperidinepropionate ,
cyanomethyl 4 -morpholinepropionate ,
2 - cyanoethyl 1 -pyrrolidinepropionate ,
2 - cyanoethyl 1 -piperidinepropionate , and
2-cyanoethyl 4 -morpholinepropionate .
The basic compounds may be used alone or in admixture
of two or more. The basic compound is preferably formulated
in an amount of 0 to 2 parts, and especially 0.01 to 1 part
by weight, per 100 parts by weight of the solids in the
resist composition. The use of more than 2 parts of the
basis compound would result in too low a sensitivity.
Component (E)
Illustrative, non- limiting, examples of the organic
acid derivatives (E) include phenol, cresol, catechol,
resorcinol , pyrogallol , f luoroglycin ,
bis ( 4 -hydroxyphenyl ) methane , 2 , 2 -bis ( 4 1 - hydr oxypheny 1 ) propane ,
bis ( 4 -hydroxyphenyl ) sulf one ,
-63-
1.1. 1- tris ( 4 ' -hydroxyphenyl) ethane ,
1.1. 2- tris(4 ' -hydroxyphenyl) ethane, hydroxybenzophenone ,
4-hydroxyphenylacetic acid # 3-hydroxyphenylacetic acid,
2-hydroxyphenylacetic acid, 3- ( 4 -hydroxyphenyl) propionic acid,
5 3- ( 2 -hydroxyphenyl) propionic acid,
2,5- dihydroxyphenylacetic acid ,
3 , 4-dihydroxyphenylacetic acid, 1 , 2-phenylenediacetic acid,
1 . 3- phenylenediacetic acid, 1 , 4 -phenylenediacetic acid,
1 , 2 -phenylenedioxydiacetic acid ,
io 1 , 4-phenylenedipropanoic acid, benzoic acid, salicylic acid,
4 . 4 - bis ( 4 1 -hydroxyphenyl) valeric acid,
4 - tert -butoxyphenylacetic acid ,
4- ( 4 -hydroxyphenyl) butyric acid,
3 , 4-dihydroxymandelic acid, and 4-hydroxymandelic acid. Of
15 these, salicylic acid and
4 , 4 -bis ( 4 1 -hydroxyphenyl ) valeric acid are preferred . They
may be used alone or in admixture of two or more.
In the resist composition comprising the
sulf onyldiazomethane as the photoacid generator according to
20 the invention, the organic acid derivative is preferably
formulated in an amount of up to 5 parts, and especially up
to 1 part by weight, per 100 parts by weight of the solids in
the resist composition. The use of more than 5 parts of the
organic acid derivative would result in too low a resolution.
25 Depending on the combination of the other components in the
resist composition, the organic acid derivative may be
omitted.
Component (F)
30 Component (F) is an organic solvent. Illustrative,
non-limiting, examples include butyl acetate, amyl acetate,
cyclohexyl acetate, 3-methoxybutyl acetate,
methyl ethyl ketone, methyl amyl ketone, cyclohexanone ,
cyclopentanone, 3-ethoxyethyl propionate,
35 3-ethoxymethyl propionate, 3-methoxymethyl propionate,
methyl acetoacetate , ethyl acetoacetate , diacetone alcohol,
methyl pyruvate, ethyl pyruvate.
-64-
propylene glycol monomethyl ether,
propylene glycol monoethyl ether,
propylene glycol monomethyl ether propionate,
propylene glycol monoethyl ether propionate,
5 ethylene glycol monomethyl ether,
ethylene glycol monoethyl ether,
diethylene glycol monomethyl ether,
diethylene glycol monoethyl ether, 3-methyl-3-methoxybutanol,
N-methylpyrrolidone, dimethyl sulfoxide, y-butyrolactone ,
10 propylene glycol methyl ether acetate,
propylene glycol ethyl ether acetate,
propylene glycol propyl ether acetate, methyl lactate,
ethyl lactate, propyl lactate, and tetramethylsulf onic acid.
Of these, the propylene glycol alkyl ether acetates and alkyl
15 lactates are especially preferred. The solvents may be used
alone or in admixture of two or more. An exemplary useful
solvent mixture is a mixture of a propylene glycol alkyl
ether acetate and an alkyl lactate. It is noted that the
alkyl groups of the propylene glycol alkyl ether acetates are
20 preferably those of 1 to 4 carbon atoms, for example, methyl,
ethyl and propyl, with methyl and ethyl being especially
preferred. Since the propylene glycol alkyl ether acetates
include 1,2- and 1 , 3 -substituted ones, each includes three
isomers depending on the combination of substituted positions,
25 which may be used alone or in admixture.
When the propylene glycol alkyl ether acetate is used
as the solvent, it preferably accounts for at least 50% by
weight of the entire solvent. Also when the alkyl lactate is
used as the solvent, it preferably accounts for at least 50%
30 by weight of the entire solvent. When a mixture of propylene
glycol alkyl ether acetate and alkyl lactate is used as the
solvent, that mixture preferably accounts for at least 50% by
weight of the entire solvent. In this solvent mixture, it is
further preferred that the propylene glycol alkyl ether
35 acetate is 60 to 95% by weight and the alkyl lactate is 40 to
5% by weight. A lower proportion of the propylene glycol
alkyl ether acetate would invite a problem of inefficient
-65-
coating whereas a higher proportion thereof would provide
insufficient dissolution and allow for particle and foreign
matter formation. A lower proportion of the alkyl lactate
would provide insufficient dissolution and cause the problem
5 of many particles and foreign matter whereas a higher
proportion thereof would lead to a composition which has a
too high viscosity to apply and loses storage stability.
The solvent is preferably used in an amount of 300 to
2,000 parts by weight, especially 400 to 1,000 parts by
10 weight per 100 parts by weight of the solids in the resist
composition. The solvent concentration is not limited
thereto as long as a film can be formed by existing methods.
Component (G)
15 In one preferred embodiment, the resist composition
further contains (G) a compound with a molecular weight of up
to 3,000 which changes its solubility in an alkaline
developer under the action of an acid, that is, a dissolution
inhibitor. Typically, a compound obtained by partially or
20 entirely substituting acid labile substituents on a phenol or
carboxylic acid derivative having a molecular weight of up to
2,500 is added as the dissolution inhibitor.
Examples of the phenol or carboxylic acid derivative
having a molecular weight of up to 2,500 include
25 bisphenol A, bisphenol H, bisphenol S,
4 , 4 -bis ( 4 1 -hydroxyphenyl) valeric acid,
tris ( 4 -hydroxyphenyl) methane ,
1.1.1- tris(4'- hydroxyphenyl ) ethane ,
1.1.2- tris ( 4 ' -hydroxyphenyl ) ethane , phenolphthalein , and
30 thymolphthalein . The acid labile substituents are the same
as those exemplified as the acid labile groups in the polymer.
Illustrative, non-limiting, examples of the
dissolution inhibitors which are useful herein include
bis (4- (2 1 -tetrahydropyranyloxy ) phenyl) methane,
35 bis (4- (2 ' -tetrahydrof uranyloxy) phenyl) methane,
bis ( 4- tert-butoxyphenyl) methane ,
bis ( 4- tert-butoxycarbonyloxyphenyl ) methane ,
-66-
bis ( 4 - t ert -but oxycarbonylmethyloxyphenyl ) methane ,
bis (4- ( 1 1 -ethoxyethoxy) phenyl) methane,
bis ( 4 - ( 1 1 - ethoxypropyloxy ) phenyl ) methane ,
2 , 2-bis( 4 ' - (2" - tetrahydropyranyloxy ) ) propane,
2 , 2 -bis ( 4 1 - ( 2 " - tetrahydrof uranyloxy ) phenyl ) propane ,
2 , 2 -bis ( 4 ' -tert-butoxyphenyl) propane,
2 , 2-bis( 4 f -tert-butoxycarbonyloxyphenyl) propane,
2 , 2 -bis ( 4-tert -but oxycarbonylmethyloxyphenyl) propane,
2,2-bis(4 , -(l" - ethoxyethoxy ) phenyl ) propane ,
2 , 2 -bis ( 4 1 - ( 1 " - ethoxypropyloxy ) phenyl ) propane ,
tert- butyl 4, 4 -bis (4 ' -( 2 " -tetrahydropyranyloxy) phenyl ) -
valerate ,
tert -butyl 4 , 4 -bis ( 4 1 - ( 2 " - tetrahydrof uranyloxy ) phenyl ) -
valerate ,
tert -butyl 4, 4 -bis (4 ' -tert -butoxyphenyl) valerate,
tert-butyl 4 , 4-bis ( 4-tert - but oxycarbonyloxyphenyl) valerate,
tert -butyl 4, 4-bis ( 4 ' - tert-butoxycarbonylmethyloxyphenyl) -
valerate,
tert-butyl 4 , 4-bis ( 4 1 - ( 1 " -ethoxyethoxy ) phenyl ) valerate ,
tert-butyl 4 , 4 -bis ( 4 1 - ( 1 " - ethoxypropyloxy ) phenyl ) valerate ,
tris(4- (2 1 -tetrahydropyranyloxy) phenyl) methane,
tris( 4- (2 1 -tetrahydrof uranyloxy) phenyl) methane,
tris ( 4 - tert -butoxyphenyl ) methane ,
tris ( 4 - tert-butoxycarbonyloxyphenyl ) methane ,
tris ( 4 - tert - but oxycarbonyloxymethylphenyl ) methane ,
tris ( 4 - ( 1 ' - ethoxyethoxy ) phenyl ) methane ,
tris ( 4 - ( 1 1 - ethoxypropyloxy ) phenyl ) methane ,
1,1,2- tris ( 4 1 - ( 2 " - tetrahydropyranyloxy ) phenyl ) ethane ,
1,1,2- tris ( 4 1 - ( 2 " - tetrahydrof uranyloxy ) phenyl ) ethane ,
1 , 1 , 2- tris ( 4 ' -tert -butoxyphenyl) ethane,
1,1,2- tris ( 4 1 - tert-butoxycarbonyloxyphenyl ) ethane ,
1 , 1 , 2- tris ( 4 * -tert -but oxycarbonylmethyloxyphenyl) ethane ,
1,1, 2 -tris ( 4 ' - ( 1 ■ -ethoxyethoxy) phenyl) ethane, and
1 , 1 , 2 - tris ( 4 ' - ( 1 ' - ethoxypropyloxy ) phenyl ) ethane .
In the resist composition comprising the
sulfonyldiazomethane of formula (1) or (la) as the photoacid
generator according to the invention, an appropriate amount
-67-
of the dissolution inhibitor is up to 20 parts, and
especially up to 15 parts by weight per 100 parts by weight
of the solids in the resist composition. With more than 20
parts of the dissolution inhibitor, the resist composition
becomes less heat resistant because of an increased content
of monomer components.
Component (H)
In a chemical amplification, negative working, resist
composition as well, the sulf onyldiazomethane of formula (1)
or (la) according to the invention may be used as the
photoacid generator. This composition further contains an
alkali- soluble resin as component (H) , examples of which are
intermediates of the above-described component (A) though not
limited thereto. Examples of the alkali- soluble resin
include poly (p -hydroxys tyrene) , poly (m-hydroxystyrene) ,
poly ( 4 -hydroxy- 2 -methyls tyrene) ,
poly ( 4 -hydroxy- 3 -methyls tyrene ) ,
poly (ct-methyl-p-hydroxystyrene) ,
partially hydrogenated p- hydroxys tyrene copolymers,
p-hydroxystyrene-a-methyl-p-hydroxystyrene copolymers ,
p-hydroxystyrene-a-methylstyrene copolymers,
p-hydroxystyrene-styrene copolymers ,
p-hydroxystyrene-m-hydroxystyrene copolymers ,
p-hydroxystyrene-styrene copolymers ,
p- hydroxys tyrene -acrylic acid copolymers,
p-hydroxystyrene-methacrylic acid copolymers,
p- hydroxys tyrene -methyl methacrylate copolymers,
p-hydroxystyrene-acrylic acid-methyl methacrylate copolymers,
p- hydroxys tyrene -methyl acrylate copolymers,
p-hydroxystyrene-methacrylic acid-methyl methacrylate
copolymers ,
poly(methacrylic acid), poly(acrylic acid),
acrylic acid-methyl acrylate copolymers,
methacrylic acid-methyl methacrylate copolymers,
acrylic acid-maleimide copolymers,
-68-
methacrylic acid-maleimide copolymers,
p-hydroxystyrene-acrylic acid-maleimide copolymers, and
p-hydroxystyrene-methacrylic acid-maleimide copolymers, but
are not limited to these combinations.
Preferred are poly (p -hydroxys tyrene) ,
partially hydrogenated p- hydroxys tyrene copolymers,
p -hydroxys tyrene -s tyrene copolymers ,
p- hydroxys tyrene -acrylic acid copolymers, and
p-hydroxystyrene-methacrylic acid copolymers.
Alkali-soluble resins comprising units of the
following formula (2), (2 1 ), (2") or (2"') are especially
preferred.
-69-
I
— CH 7 — C
(R 5 )x-
(OH) y
R"
O OH
(OH) y
(2)
r
-(CH-C)^ ^CH-CH-jj -fcH 2 -cV
,\^(R 5 )x
(OH)^
(OH) y
(2»)
R R 4
— (-CH 2 -c4i fcHa-C^j-
(R 5 ) x -
(R 5 )x-
(OH) y
(ZZ)
_J XX
(2"')
-70-
Herein R 4 is hydrogen or methyl; and R 5 is a straight,
branched or cyclic alkyl group of 1 to 8 carbon atoms . The
subscript x is 0 or a positive integer; y is a positive
integer, satisfying x+y ^ 5, yy is 0 or a positive integer,
5 satisfying x+yy ^ 5; M and N are positive integers,
satisfying 0 < N/(M+N) <; 0.5; A and B are positive integers,
C is 0 or a positive integer, satisfying 0 < B/(A+B+C) ^ 0.5,
ZZ is a divalent group selected from among CH 2 , CH(OH),
CR 5 (OH) , C=0 and C(OR 5 )(OH), or a trivalent organic group
10 represented by -C(OH)=; F is independently a positive integer,
and H is a positive integer, satisfying 0.001 <; H/(H+F) <s
0.1; and XX is 1 or 2 .
The polymer should preferably have a weight average
molecular weight (Mw) of 3,000 to 100,000. Many polymers
15 with Mw of less than 3,000 do not perform well and are poor
in heat resistance and film formation. Many polymers with Mw
of more than 100,000 give rise to a problem with respect to
dissolution in the resist solvent and developer. The polymer
should also preferably have a dispersity (Mw/Mn) of up to 3.5,
20 and more preferably up to 1.5. With a dispersity of more
than 3.5, resolution is low in many cases. Although the
preparation method is not critical, a poly (p -hydroxys tyrene)
or similar polymer with a low dispersity or narrow dispersion
can be synthesized by living anion polymerization.
25 To impart a certain function, suitable substituent
groups may be introduced into some of the phenolic hydroxyl
and carboxyl groups on the foregoing polymer. Exemplary and
preferred are substituent groups for improving adhesion to
the substrate, substituent groups for improving etching
30 resistance, and especially substituent groups which are
relatively stable against acid and alkali and effective for
controlling such that the dissolution rate in an alkali
developer of unexposed and low exposed areas of a resist film
may not become too high. Illustrative, non- limiting,
35 substituent groups include 2 -hydroxy ethyl, 2-hydroxypropyl,
methoxymethyl , methoxycarbonyl , ethoxycarbonyl ,
-71-
methoxycarbonylmethyl , ethoxycarbonylmethyl ,
4 -methyl - 2 - oxo - 4 - oxolanyl , 4 -me thyl - 2 - oxo - 4 - oxanyl , methyl ,
ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, acetyl,
pivaloyl, adamantyl, isobornyl, and cyclohexyl. It is also
possible to introduce acid-decomposable substituent groups
such as t-butoxycarbonyl and relatively acid-undecomposable
substituent groups such as t -butyl and t - but oxycarbonylme thyl .
In the resist composition, the above resin is blended
in any desired amount, preferably of 65 to 99 parts by weight,
especially 70 to 98 parts by weight per 100 parts by weight
of the solids.
Also contained in the negative resist composition is
(I) an acid crosslinking agent capable of forming a
crosslinked structure under the action of an acid. Typical
acid crosslinking agents are compounds having at least two
hydroxymethyl, alkoxymethyl , epoxy or vinyl ether groups in a
molecule. Substituted glycoluril derivatives, urea
derivatives, and hexa(methoxymethyl)melamine compounds are
suitable as the acid crosslinking agent in the chemically
amplified, negative resist composition comprising the
sulf onyldiazomethane . Examples include
N , N , N 1 , N ■ - tetramethoxymethylurea , hexamethoxymethylmelamine ,
tetraalkoxymethyl- substituted glycoluril compounds such as
tetrahydroxymethyl-substituted glycoluril and
tetramethoxymethylglycoluril, and condensates of phenolic
compounds such as substituted or unsubstituted
bis(hydroxymethylphenol) compounds and bisphenol A with
epichlorohydrin . Especially preferred acid crosslinking
agents are 1 , 3 , 5 , 7- tetraalkoxymethylglycolurils such as
1,3,5,7 - tetramethoxymethylglycoluril ,
1,3,5,7- tetrahydroxymethylglycoluril ,
2 , 6-dihydroxymethyl-p-cresol , 2 , 6-dihydroxymethylphenol ,
2 , 2 ' , 6 , 6 ' -tetrahydroxymethyl -bisphenol A,
1 , 4 -bis [ 2- ( 2-hydroxypropyl) ] benzene,
N , N , N 1 , N 1 - tetramethoxymethylurea , and
hexamethoxymethylmelamine .
-72-
An appropriate amount of the acid crosslinking agent
is, but not limited thereto, about 1 to 20 parts, and
especially about 5 to 15 parts by weight per 100 parts by
weight of the solids in the resist composition. The acid
crosslinking agents may be used alone or in admixture of any.
Component (J) is an alkali-soluble compound having a
molecular weight of up to 2,500. Any suitable compound may
be used although a compound having at least two phenol and/or .
carboxyl groups is preferred. Illustrative, non-limiting,
examples of the alkali- soluble compound (J) include
cresol, catechol, resorcinol, pyrogallol, f luoroglycin ,
bis ( 4 -hydroxyphenyl ) methane , 2 , 2 -bis ( 4 1 -hydroxyphenyl ) propane ,
bis ( 4 -hydroxyphenyl ) sulf one ,
1 . 1 . 1- tris ( 4 1 -hydroxyphenyl) ethane,
1.1.2- tris ( 4 1 -hydroxyphenyl ) ethane , hydroxybenzophenone ,
4-hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid,
2 - hydroxyphenylacet ic acid , 3 - ( 4 -hydroxyphenyl ) propionic acid ,
3 - ( 2 -hydroxyphenyl ) propionic acid ,
2,5- dihydr oxyphenylace t ic acid ,
3 , 4-dihydroxyphenylacetic acid,
1 , 2-phenylenediacetic acid, 1 , 3-phenylenediacetic acid,
1,4-phenylenediacetic acid, 1 , 2-phenylenedioxydiacetic acid,
1 , 4-phenylenedipropanoic acid, benzoic acid, salicylic acid,
4 , 4 -bis ( 4 1 -hydroxyphenyl) valeric acid,
4- tert-butoxyphenylacetic acid,
4-(4-hydroxyphenyl)butyric acid, 3 , 4-dihydroxymandelic acid,
and 4-hydroxymandelic acid. Of these, salicylic acid and
4 , 4-bis(4 1 -hydroxyphenyl) valeric acid are preferred. They
may be used alone or in admixture of two or more. The
alkali- soluble compound is blended in any desired amount,
preferably of 0 to 20 parts by weight, especially 2 to 10
parts by weight per 100 parts by weight of the solids in the
resist composition .
In the chemical amplification type resist composition
according to the invention, there may be added such additives
as a surfactant for improving coating, and a light absorbing
agent for reducing diffuse reflection from the substrate.
-73-
Illustrative, non- limiting, examples of the surfactant
include nonionic surfactants, for example, polyoxyethylene
alkyl ethers such as polyoxyethylene lauryl ether,
polyoxyethylene stearyl ether, polyoxyethylene cetyl ether,
and polyoxyethylene oleyl ether, polyoxyethylene alkylaryl
ethers such as polyoxyethylene octylphenol ether and
polyoxyethylene nonylphenol ether, polyoxyethylene
polyoxypropylene block copolymers, sorbitan fatty acid esters
such as sorbitan monolaurate, sorbitan monopalmitate, and
sorbitan monostearate , and polyoxyethylene sorbitan fatty
acid esters such as polyoxyethylene sorbitan monolaurate,
polyoxyethylene sorbitan monopalmitate,
polyoxyethylene sorbitan monostearate,
polyoxyethylene sorbitan trioleate, and
polyoxyethylene sorbitan tristearate; f luorochemical
surfactants such as EFTOP EF301, EF303 and EF352 (Tohkem
Products Co., Ltd.). Megaface F171, F172 and F173 (Dainippon
Ink & Chemicals, Inc.), Fluorad FC430 and FC431 (Sumitomo 3M
Co., Ltd.), Aashiguard AG710, Surflon S-381, S-382, SC101,
SC102, SC103, SC104, SC105, SC106, Surfynol E1004, KH-10,
KH-20, KH-30 and KH-40 (Asahi Glass Co., Ltd.);
organosiloxane polymers KP341, X-70-092 and X-70-093
(Shin-Etsu Chemical Co., Ltd.), acrylic acid or methacrylic
acid Polyflow No. 7 5 and No. 9 5 (Kyoeisha Ushi Kagaku Kogyo
K.K.). Inter alia, FC430, Surflon S-381, Surfynol E1004,
KH-20 and KH-30 are preferred. These surfactants may be used
alone or in admixture.
In the chemical amplification type resist composition
according to the invention, the surfactant is preferably
formulated in an amount of up to 2 parts, and especially up
to 1 part by weight, per 100 parts by weight of the solids in
the resist composition.
In the chemical amplification type resist composition
according to the invention, a UV absorber may be added.
Those UV absorbers described in JP-A 11-190904 are useful,
but the invention is not limited thereto. Exemplary UV
absorbers are diaryl sulfoxide derivatives such as
bis ( 4 -hydroxyphenyl ) sulfoxide ,
bis ( 4-tert-butoxyphenyl) sulfoxide,
bis ( 4 - tert - but oxycarbonyloxyphenyl ) sulfoxide , and
bis [ 4- ( 1-ethoxyethoxy ) phenyl] sulfoxide;
diarylsulfone derivatives such as bis ( 4 -hydroxyphenyl ) sulf one,
bis ( 4-tert-butoxyphenyl) sulf one ,
bis ( 4 - t ert -but oxycarbonyloxyphenyl ) sulf one ,
bis [ 4- ( 1-ethoxyethoxy ) phenyl] sulf one, and
bis [ 4 - ( 1 - ethoxypropoxy ) phenyl ] sulf one ;
diazo compounds such as benzoquinonediazide ,
naphthoquinonediazide , anthraquinonediazide , diazof luorene ,
diazotetralone, and diazophenanthrone; quinonediazide
group -containing compounds such as complete or partial ester
compounds between naphthoquinone- 1 , 2-diazide- 5 -sulf onic acid
chloride and 2 , 3 , 4- trihydroxybenzophenone and complete or
partial ester compounds between naphthoquinone- 1 , 2-diazide-4-
sulfonic acid chloride and 2 , 4 , 4 ' -trihydroxybenzophenone ;
tert - butyl 9 - anthracenecarboxylat e ,
tert -amyl 9 -anthracenecarboxylate ,
tert -methoxymethyl 9 - anthracenecarboxylate ,
tert-ethoxyethyl 9 -anthracenecarboxylate,
2-tert-tetrahydropyranyl 9 - anthracenecarboxylate , and
2-tert-tetrahydrofuranyl 9 - anthracenecarboxylate , The UV
absorber may or may not be added to the resist composition
depending on the type of resist composition. An appropriate
amount of UV absorber, if added, is 0 to 10 parts, more
preferably 0.5 to 10 parts, most preferably 1 to 5 parts by
weight per 100 parts by weight of the base resin.
For the microf abrication of integrated circuits, any
well-known lithography may be used to form a resist pattern
from the chemical amplification type resist composition
comprising the sulf onyldiazomethane photoacid generator of
formula (1) or (la) and the resin which changes solubility in
an alkaline developer under the action of acid according to
the invention.
The composition is applied onto a substrate (e.g., Si,
Si0 2 , SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-ref lecting
film, etc.) by a suitable coating technique such as spin
coating, roll coating, flow coating, dip coating, spray-
coating or doctor coating. The coating is prebaked on a hot
plate at a temperature of 60 to 150° C for about 1 to 10
minutes, preferably 80 to 120° C for 1 to 5 minutes. The
resulting resist film is generally 0.1 to 2.0 \xm thick. With
a mask having a desired pattern placed above the resist film,
the resist film is then exposed to actinic radiation,
preferably having an exposure wavelength of up to 300 nm,
such as UV, deep-UV, electron beams, x-rays, excimer laser
light, y-rays and synchrotron radiation in an exposure dose
of about 1 to 200 mJ/cm 2 , preferably about 10 to 100 mJ/cm 2 .
The film is further baked on a hot plate at 60 to 150° C for 1
to 5 minutes, preferably 80 to 120° C for 1 to 3 minutes
(post -exposure baking = PEB) .
Thereafter the resist film is developed with a
developer in the form of an aqueous base solution, for
example, 0.1 to 5%, preferably 2 to 3% aqueous solution of
tetramethylammonium hydroxide ( TMAH) for 0.1 to 3 minutes,
preferably 0.5 to 2 minutes by conventional techniques such
as dipping, puddling or spraying. In this way, a desired
resist pattern is formed on the substrate. It is appreciated
that the resist composition of the invention is best suited
for micro-patterning using such actinic radiation as deep UV
with a wavelength of 2 54 to 193 nm, vacuum UV with a
wavelength of 157 nm, electron beams, x-rays, excimer laser
light, y-rays and synchrotron radiation. With any of the
above-described parameters outside the above -described range,
the process may sometimes fail to produce the desired pattern.
EXAMPLE
Examples of the invention are given below by way of
illustration and not by way of limitation.
Synthesis Example 1
Synthesis of 2- (n-hexyloxy) -5-tert-butylthiophenol
In 158 g of ethanol were dissolved 105 g (0.7 mol) of
4-tert-butylphenol and 30.8 g (0.77 mol) of sodium hydroxide.
5 To the solution at 70° C, 127 g (0.77 mol) of n-bromohexane
was added dropwise. The solution was allowed to ripen for 4
hours and cooled to room temperature, after which 158 g of
water was added. The oily phase was separated therefrom and
concentrated on a rotary evaporator, yielding 167 g of an
10 oily matter. Then 167 g of the oily matter was dissolved in
600 g of dichloromethane. While cooling in an ice/water bath,
100 g (0.625 mol) of bromine was added dropwise at a
temperature below 10° C. After the completion of dropwise
addition, 300 g of water was added. The organic layer was
15 separated and washed with a saturated sodium hydrogen
carbonate aqueous solution. The organic layer was
concentrated on a rotary evaporator, yielding 208 g of an
oily matter. On analysis by gas chromatography /mass analysis
and gas chromatography, the oily matter was found to contain
20 90% of 2-bromo-4-tert-butyl-l-n-hexyloxybenzene .
Using 208 g (0.60 mol) of the 2-bromo-4-tert-butyl-l-
n-hexyloxybenzene (90% pure), 15.4 g (0.63 mol) of metallic
magnesium and 450 g of tetrahydrof uran , a Grignard reagent
was prepared in a conventional manner. The Grignard reagent
25 was ice cooled, to which 18.3 g (0.57 mol) of colloidal
sulfur was added at a temperature below 20° C. The solution
was allowed to ripen for 2 hours at room temperature, then
ice cooled again. To the solution, 90 g of cone,
hydrochloric acid (12N) and 300 g of water were added. The
30 organic layer was separated and concentrated on a rotary
evaporator, yielding 180 g of an oily matter. This
concentrate was distilled in vacuum (boiling point
132-135° C/0. 5 Torr) , obtaining 115 g of the end compound,
2- (n-hexyloxy) -5-tert-butylthiophenol with a purity of 90%
35 (yield 64%) .
-77-
Synthesis Example 2
Synthesis of bis ( 2- (n-hexyloxy ) -5-tert-butylbenzenesulf onyl) -
methane
In 230 g of ethanol were dissolved 115 g (0.39 mol) of
the above 2- (n-hexyloxy ) -5-tert-butylthiophenol and 16.4 g
(0.41 mol) of sodium hydroxide. Then 23.1 g (0.27 mol) of
dichloromethane was added dropwise at a temperature below
50° C. The solution was heated on an oil bath to 60° C and
allowed to ripen at the temperature for 3 hours. The
solution was allowed to cool down to room temperature, after
which 420 g of water and 300 g of dichloromethane were added.
The organic layer was separated and the solvent was removed
by means of a rotary evaporator, yielding 124 g of
formaldehyde bis ( 2 - ( n-hexyloxy ) - 5 - tert -butylbenzenethio ) -
acetal .
To 400 g of acetonitrile were added 124 g of the
formaldehyde bis(2- (n-hexyloxy) - 5- tert-butylbenzenethio ) -
acetal and 1.9 g (0.0058 mol) of sodium tungstate. The
solution was heated on an oil bath to 70° C. Then 94 g (0.97
mol) of 35% aqueous hydrogen peroxide was added dropwise at a
temperature below 75° C. The solution was held at the
temperature for 4 hours and then cooled on an ice bath
whereupon white crystals precipitated. The crystals were
filtered, collecting 95 g (yield 80%) of the end
bis ( 2- ( n-hexyloxy) - 5- tert -butylbenzenesulf onyl ) methane .
Synthesis Example 3
Synthesis of bis ( 2- (n-hexyloxy ) -5-tert-butylbenzenesulf onyl) -
diazomethane
In 120 g of dichloromethane were dissolved 12.1 g
(0.02 mol) of the above bis ( 2- (n-hexyloxy) -5-tert-
butylbenzenesulf onyl )methane and 5.9 g (0.03 mol) of
p-toluenesulf onylazide. The solution was cooled on an ice
bath, and 3.0 g (0.02 mol) of 1 , 8-diazabicyclo [ 5 . 4 . 0 ] - 7-
undecene (DBU) was added at a temperature below 5°C. The
solution was allowed to ripen at room temperature for 2 hour,
after which 100 g of water was added. The organic layer was
-78-
separated and washed with 100 g of water, after which the
solvent was removed by means of a rotary evaporator,
obtaining 35 g of an oily matter. It was purified by silica
gel column chromatography (eluent: dichloromethane) ,
5 obtaining 4.5 g (yield 35%) of the end compound,
bis ( 2 - ( n-hexyloxy ) - 5 - tert -butylbenzenesulf onyl ) diazomethane .
The thus obtained bis ( 2- (n-hexyloxy ) -5-tert-
butylbenzenesulf onyl) diazomethane was analyzed by nuclear
magnetic resonance (NMR) spectroscopy, infrared (IR)
10 absorption spectroscopy and thermogravimetric analysis (Tdec),
with the results shown below.
Ha Hb He Hd He Hf
I I I I I I
H 9 C- CH- CH- CH- CH- CH
I
Hg v O
so 2 — c— so 2
HoC C CHi
Hi CH 3
^-NMR: CDC1 3 (ppm)
(1)
Ha
0.887-0.934
triplet
6H
15 (2)
Hb,
He
1.30-1.40
multiplet
8H
(3)
Hi
1.296
singlet
18H
(4)
Hd
1.430-1.527
multiplet
4H
(5)
He
1 .812-1 .908
multiplet
4H
(6)
Hf
4.051-4.096
triplet
4H
20 (7)
Hg
6.878-6.907
doublet
2H
(8)
Hh
7.510-7.547
quadruplet
2H
(9)
Hj
7.800-7.808
doublet
2H
IR (cm- 1 )
: 2960.
2873,
2859, 2121, 1497,
1466, 1365,
135C
1336,
1294,
1269, 1169, 1149,
1066, 982.
829,
25 594, 580, 552
Thermogravimetric analysis: 14 6. 6° C (the temperature at which
a weight change of -0.1 wt% occurred upon heating
at a rate of 10°C/min from room temperature)
-79-
Synthesis Example 4
Synthesis of 2- (n-hexyloxy ) -5-methylthiophenol
In 92 g of ethanol were dissolved 46,7 g (0.25 mol) of
2-bromo-4-methylphenol and 11.0 g (0.275 mol) of sodium
5 hydroxide. To the solution at 70° C, 45.4 g (0.275 mol) of
n-bromohexane was added dropwise. The solution was allowed
to ripen for 4 hours and cooled to room temperature, after
which 190 g of water was added. The oily phase was separated
therefrom and concentrated on a rotary evaporator, yielding
10 67 g of an oily matter. On analysis by gas
chromatography/mass analysis and gas chromatography, the oily
matter was found to contain 95% of 2-bromo-4- tert-butyl-l-n-
hexyloxybenzene .
Using 67 g (0.235 mol) of the 2-bromo-4-tert-butyl-l-
15 n-hexyloxybenzene (95% pure), 6.1 g (0.25 mol) of metallic
magnesium and 163 g of tetrahydrof uran , a Grignard reagent
was prepared in a conventional manner. The Grignard reagent
was ice cooled, to which 7.45 g (0.23 mol) of colloidal
sulfur was added at a temperature below 20° C. The solution
20 was allowed to ripen for 2 hours at room temperature, then
ice cooled again. To the solution, 38 g of cone,
hydrochloric acid (12N) and 125 g of water were added. The
organic layer was separated and concentrated on a rotary
evaporator, yielding 54 g of an oily matter. This
25 concentrate was distilled in vacuum (boiling point
120-128° C/0 . 5 Torr) , obtaining 39 g of the end compound,
2- (n-hexyloxy) -5-methylthiophenol with a purity of 97% (yield
70%) .
30 Synthesis Example 5
Synthesis of bis (2- (n-hexyloxy) -5-methylbenzenesulf onyl ) -
methane
In 80 g of ethanol were dissolved 39 g (0.167 mol) of
the above 2- (n-hexyloxy ) -5-methylthiophenol and 7.0 g (0.175
35 mol) of sodium hydroxide. Then 9.9 g (0.117 mol) of
dichloromethane was added dropwise at a temperature below
50° C. The solution was heated on an oil bath to 60° C and
-80-
allowed to ripen at the temperature for 3 hours. The
solution was allowed to cool down to room temperature, after
which 160 g of water and 200 g of dichloromethane were added.
The organic layer was separated and the solvent was removed
5 by means of a rotary evaporator, yielding 42 g of
formaldehyde bis ( 2 - (n-hexyloxy ) - 5 -methylbenzenethio ) acetal .
To 156 g of acetonitrile were added 42 g of the
formaldehyde bis ( 2 - ( n-hexyloxy ) - 5 -methylbenzenethio ) acetal
and 0.8 g (0.0025 mol) of sodium tungstate. The solution was
10 heated on an oil bath to 70° C. Then 40.5 g (0.417 mol) of
35% aqueous hydrogen peroxide was added dropwise at a
temperature below 7 5° C. The solution was held at the
temperature for 4 hours and then cooled on an ice bath
whereupon white crystals precipitated. The crystals were
15 filtered, collecting 40 g (yield 91%) of the end
bis (2- (n-hexyloxy) - 5-methylbenzenesulf onyl)methane .
Synthesis Example 6
Synthesis of bis ( 2- (n-hexyloxy ) -5-methylbenzenesulf onyl) -
20 diazomethane
In 100 g of dichloromethane were dissolved 10.0 g
(0.019 mol) of the above bis (2- (n-hexyloxy) -5-methylbenzene-
sulf onyl ) methane and 5.6 g (0.0285 mol) of
p-toluenesulf onylazide . The solution was cooled on an ice
25 bath, and 2.89 g (0.019 mol) of 1 , 8-diazabicyclo [ 5 . 4 . 0 ] -7-
undecene (DBU) was added at a temperature below 5°C. The
solution was allowed to ripen at room temperature for 2 hour,
after which 100 g of water was added. The organic layer was
separated and washed with 100 g of water, after which the
30 solvent was removed by means of a rotary evaporator,
obtaining 20 g of an oily matter. It was purified by silica
gel column chromatography (eluent: dichloromethane),
obtaining 7.4 g (yield 71%) of the end compound,
bis ( 2- (n-hexyloxy ) -5-methylbenzenesulf onyl) diazomethane . It
35 was analyzed by NMR, IR and thermogravimetric analysis, with
the results shown below.
-81-
Ha Hb He Hd He Hf
I I I I I I
H 2 C-CH-CH-CH-CH-CH (CH 2 ) 5 CH 3
^-NMR: CDCI3 (ppm)
(1)
Ha
0.883-0.930
triplet
6H
(2)
Hb,
He
1.274-1.40
multiplet
8H
5 (3)
Hd
1.40-1. 512
multiplet
4H
(4)
He
1.797-1.893
multiplet
4H
(5)
Hi
2.275
singlet
6H
(6)
Hf
3.992-4.037
triplet
4H
(7)
Hg
6.761-6.790
doublet
2H
10 (8)
Hh
7.242-7.279
quadruplet
2H
(9)
Hj
7.540-7.549
quadruplet
2H
IR (cm" 1 )
: 2954,
2931
, 2129, 1610, 1570,
1498, 1464,
1392
1344,
1331
, 1286, 1255, 1232,
1143, 1065,
993,
823.
723,
694, 646. 598. 588,
569, 540
15 Thermogravimetric analysis: 148° C (the temperature at which a
weight change of -0.1 wt% occurred upon heating at
a rate of 10° C/min from room temperature)
Synthesis Example 7
20 Synthesis of bis ( 2- (n-hexyloxy ) -5-ethylbenzenesulf onyl ) -
diazomethane
The end compound, bis ( 2- ( n-hexyloxy ) -5-ethylbenzene-
sulf onyl ) diazomethane was synthesized as in Synthesis
Examples 1 to 3 except that 4-ethylphenol was used instead of
25 4-tert-butylphenol in Synthesis Example 1. The results of
NMR, IR and thermogravimetric analyses are shown below.
-82-
10
Ha Hb He Hd He Hf
I I I I I I
H 2 C— C— C— C— C— CH (CH 2 ) 5 CH 3
H H H H | ^| 2,5 3
Hg v O O
1 H-NMR : CDCl, (ppm)
(1) Ha
0 . 883-0 . 930
triplet
6H
(2) Hk
1.165-1.215
triplet
6H
(3) Hb. He
1.292-1.40
multiplet
8H
(4) Hd
1 . 40-1 . 515
multiplet
4H
(5) He
1 . 801-1 . 896
multiplet
4H
(6) Hi
2.540-2.616
quadruplet
4H
(7) Hf
4.003-4.048
triplet
4H
(8) Hg
6.798-6.826
doublet
2H
(9) Hh
7.274-7.309
quadruplet
2H
(10) Hj
7.567-7.575
doublet
2H
IR (cm 1 ) : 2951, 2869,
2129, 1608, 1498,
1461, 1344,
1330,
1228, 1255, 1230, 1141, 1062, 993, 937, 835, 692,
15 646, 588, 555, 522
Thermogravimetric analysis: 141° C (the temperature at which a
weight change of -0.1 wt% occurred upon heating at
a rate of 10°C/min from room temperature)
20 Synthesis Example 8
Synthesis of bis ( 2- (n-hexyloxy ) -5-isopropylbenzenesulf onyl) -
diazomethane
The end compound, bis ( 2- (n-hexyloxy ) -5-isopropyl-
benzenesulf onyl ) diazomethane was synthesized as in Synthesis
25 Examples 1 to 3 except that 4 -isopropylphenol was used
instead of 4- tert-butylphenol in Synthesis Example 1. The
results of NMR, IR and thermogravimetric analyses are shown
below.
-83-
10
Ha Hb He Hd He Hf
I I I I I I
H 2 C— C— C— C— C-CH (CH 2 ) 5 CH 3
H H H H | v | 2J5 3
Hg, O O
^-NMR: CDCI3 (ppm)
(1)
Ha
0. 885-0 . 931
triplet
6H
(2)
Hk
1.203-1.226
doublet
12H
(3)
Hb,
He
1. 30-1 . 40
multiplet
8H
(4)
Hd
1.40-1.518
multiplet
4H
(5)
He
1.804-1.900
multiplet
4H
(6)
Hi
2.798-2.937
multiplet
2H
(7)
Hf
4.022-4.068
triplet
4H
(8)
Hg
6.840-6.868
doublet
2H
(9)
Hh
7.331-7.368
quadruplet
2H
(10)
7.617-7.625
doublet
2H
IR (cm 1 )
: 2958. 2931,
2871, 2127, 1606,
1494, 1465,
1344,
1330, 1290, 1255, 1162, 1143, 1062, 991, 833, 727,
15 680, 651, 586, 553
Thermogravimetric analysis: 143° C (the temperature at which a
weight change of -0.1 wt% occurred upon heating at
a rate of 10° C/min from room temperature)
20 Synthesis Example 9
Synthesis of bis ( 2- (n-hexyloxy ) -5- ( 2 -methoxyethyl) benzene -
sulf onyl ) diazomethane
The end compound, bis ( 2- ( n-hexyloxy )- 5- ( 2 -methoxy-
ethyl )benzenesulf onyl) diazomethane was synthesized as in
25 Synthesis Examples 1 to 3 except that 4- ( 2 -methoxyethyl ) -
phenol was used instead of 4- tert-butylphenol in Synthesis
Example 1. The results of NMR, IR and thermogravimetric
analyses are shown below.
-84-
10
Ha Hb He Hd He Hf
I I I I I I
H 2 C— C— C— C— C— CH
2 H H H H I
He O
HI— CH 2
^-NMR: CDCI3 (ppm)
so 2 — c— so 2 -4 d
Hi— CH "J V Hz
Hk-CH ? H2
A o
0 I
1 CH 3
(1)
Ha
0.880-0.926
triplet
6H
(2)
Hb, He
1.28-1.40
multiplet
8H
(3)
Hd
1.40-1.513
multiplet
4H
(4)
He
1.801-1.896
multiplet
4H
(5)
Hi
2.791-2.837
triplet
4H
(6)
HI
3.329
singlet
6H
(7)
Hk
3.515-3.561
triplet
4H
(8)
Hf
4.026-4.071
triplet
4H
(9)
Hg
6.831-6.859
doublet
2H
(10)
Hh
7.344-7.380
quadruplet
2H
(11)
Hj
7.611-7.618
doublet
2H
IR (cm 1 ): 2959, 2929.
2869, 2130, 1498,
1473, 1349,
1332,
15 1286, 1257, 1143, 1116, 1064, 987, 592, 580, 551
Thermogravimetric analysis: 144° C (the temperature at which a
weight change of -0.1 wt% occurred upon heating at
a rate of 10° C/min from room temperature)
20 Reference Synthesis Example 1
Synthesis of bis ( 4-methoxyphenylsulf onyl ) diazomethane
As in Synthesis Examples 1 to 3 , the end compound was
synthesized from 4-methoxythiphenol (Tokyo Kasei Kogyo Co.,
Ltd. ) . The result of thermogravimetric analysis is shown
25 below.
-85-
Thermogravimetric analysis: 128° C (the temperature at which a
weight change of -0.1 wt% occurred upon heating at
a rate of 10° C/min from room temperature)
5 Reference Synthesis Example 2
Synthesis of bis ( 4-methylphenylsulf onyl ) diazomethane
As in Synthesis Examples 1 to 3, the end compound was
synthesized from 4-methylthiphenol (Tokyo Kasei Kogyo Co.,
Ltd.). The result of thermogravimetric analysis is shown
10 below.
Thermogravimetric analysis: 124° C (the temperature at which a
weight change of -0.1 wt% occurred upon heating at
a rate of 10° C/min from room temperature)
15 Examples 1-24 and Comparative Examples 1-3
Resist materials were formulated in accordance with
the formulation shown in Tables 1 to 3. The components used
are shown below .
Polymer A: poly (p-hydroxystyrene) in which hydroxyl groups
20 are protected with 15 mol% of 1-ethoxyethyl groups and
15 mol% of tert-butoxycarbonyl groups, having a weight
average molecular weight of 12,000.
Polymer B: poly (p-hydroxystyrene) in which hydroxyl groups
are protected with 30 mol% of 1-ethoxyethyl groups,
25 having a weight average molecular weight of 12,000.
Polymer C: poly (p-hydroxystyrene) in which hydroxyl groups
are protected with 2 5 mol% of 1-ethoxyethyl groups and
crosslinked with 3 mol% of 1 , 2-propanediol divinyl
ether, having a weight average molecular weight of
30 13,000.
Polymer D: poly (p-hydroxystyrene) in which hydroxyl groups
are protected with 28 mol% of tert-pentyl groups,
having a weight average molecular weight of 8,000.
Polymer E: p-hydroxystyrene/2-ethyl-2-adamantyl acrylate
35 copolymer having a compositional ratio (molar ratio) of
70:30 and a weight average molecular weight of 15,000.
-86-
Polymer F: p-hydroxystyrene/l-ethyl-l-norbornene methacrylate
copolymer having a compositional ratio (molar ratio) of
70:30 and a weight average molecular weight of 15,000.
Polymer G: p-hydroxystyrene/tert-butyl acrylate copolymer
having a compositional ratio (molar ratio) of 65:35 and
a weight average molecular weight of 15,000.
Polymer H: p-hydroxystyrene/l-ethylcyclopentyl methacrylate
copolymer having a compositional ratio (molar ratio) of
65:35 and a weight average molecular weight of 15,000.
Polymer I : p-hydroxystyrene/l-ethylcyclopentyl
methacrylate/p- tert-pentyloxystyrene copolymer having a
compositional ratio (molar ratio) of 70:8:22 and a
weight average molecular weight of 16,000.
Polymer J : p-hydroxystyrene/l-ethylcyclopentyl
methacrylate/ styrene copolymer having a compositional
ratio (molar ratio) of 65:10:25 and a weight average
molecular weight of 12,000.
Polymer K: p-hydroxystyrene/indene copolymer having a
compositional ratio (molar ratio) of 80:20 in which
hydroxyl groups on the hydroxys tyrene are protected
with 20 mol% of tert-butoxycarbonyl groups, and having
a weight average molecular weight of 10,000.
Polymer L : p - hydroxys tyrene / indene / 2 - ethyl - 2 - adaman tyl
methacrylate copolymer having a compositional ratio
(molar ratio) of 82:4:14 and a weight average molecular
weight of 8,000.
Polymer M : p-hydroxystyrene/indene/ 1 - ethyl- 1 -norbornene
methacrylate copolymer having a compositional ratio
(molar ratio) of 84:4:12 and a weight average molecular
weight of 8,000.
Polymer N: poly (p-hydroxy styrene) in which hydroxyl groups
are protected with 8 mol% of acetyl groups, having a
weight average molecular weight of 8,000.
PAG1 : compound of Synthesis Example 3
PAG2 : compound of Synthesis Example 6
PAG 3 : compound of Synthesis Example 7
PAG 4 : compound of Synthesis Example 8
-87-
PAG 5 : ( 4-tert-butoxyphenyl)diphenylsulf onium 10-camphor-
sulf onate
PAG 6 : bis ( 4 -methoxyphenylsulf onyl ) diazomethane
PAG 7 : bis ( cyclohexylsulf onyl ) diazomethane
5 PAG 8 : bis ( 4 -methylphenylsulf onyl ) diazomethane
PAG 9 : N-10-camphorsulf onyloxysuccinimide
Crosslinker A: 1 , 3, 5 , 7- tetramethoxymethylglycoluril
Dissolution inhibitor : bis ( 4- ( 2 1 - tetrahydropyranyloxy ) -
phenyl ) methane
10 Basic compound A: tri ( n-butyl ) amine
Basic compound B: tris ( 2-methoxyethyl ) amine
Organic acid derivative A: 4 , 4-bis ( 4 1 -hydroxyphenyl) valeric
acid
Organic acid derivative B: salicylic acid
15 Surfactant A: FC-430 (Sumitomo 3M Co., Ltd.)
Surfactant B: Surflon S-381 (Asahi Glass Co., Ltd.)
UV absorber: 9 , 10-dimethylanthracene
Solvent A: propylene glycol methyl ether acetate
Solvent B: ethyl lactate
20 The resist materials thus obtained were each filtered
through a 0.2-pm Teflon® filter, thereby giving resist
solutions. These resist solutions were spin-coated onto
silicon wafers having an organic antiref lection film (DUV-44,
Brewer Science) of 800 A thick coated thereon, so as to give
25 a dry thickness of 0.6 \xm.
The coated wafer was then baked on a hot plate at
100° C for 90 seconds. The resist films were exposed to 2/3
annular illumination using an excimer laser stepper NSR-S202A
(Nikon Corporation, NA=0.6), then baked (PEB) at 110°C for 90
30 seconds, and developed with a solution of 2.38%
tetramethylammonium hydroxide in water, thereby giving
positive patterns (Examples 1 to 23 and Comparative Examples
1-3) or negative pattern (Example 24).
The resulting resist patterns were evaluated as
35 described below.
-88-
Resist pattern evaluation
The optimum exposure dose (sensitivity Eop) was the
exposure dose which provided a 1:1 resolution at the top and
bottom of a 0.18-fxm line-and- space pattern. The minimum line
width (|jm) of a line-and-space pattern which was ascertained
separate at this dose was the resolution of a test resist.
The shape in cross section of the resolved resist pattern was
examined under a scanning electron microscope. The depth of
focus (DOF) was determined by offsetting the focal point and
judging the resist to be satisfactory when the resist pattern
shape was kept rectangular and the resist pattern film
thickness was kept above 80% of that at accurate focusing.
The PED stability of a resist was evaluated by
effecting post-exposure bake (PEB) after 24 hours of holding
from exposure at the optimum dose and determining a variation
in line width. The less the variation, the greater is the
PED stability.
The results of resist pattern evaluation are shown in
Table 4.
Other evaluation
The solubility of resist material in a solvent mixture
was examined by visual observation and in terms of clogging
upon filtration.
With respect to the applicability of a resist solution,
uneven coating was visually observed. Additionally, using an
optical interference film gage Lambda-Ace VM-3010 (Dainippon
Screen Mfg. Co., Ltd.), the thickness of a resist film on a
common wafer was measured at different positions, based on
which a variation from the desired coating thickness (0.6 \xm)
was calculated. The applicability was rated "good" when the
variation was within 0.5% (that is # within 0.003 \xm) ,
"unacceptable" when the variation was within 1%, and "poor"
when the variation was more than 1%.
Storage stability was judged in terms of foreign
matter precipitation or sensitivity change with the passage
of time. After the resist solution was aged for 100 days at
-89-
the longest, the number of particles of 0.3 p or larger per
ml of the resist solution was counted by means of a particle
counter KL-20A (Rion Co., Ltd.). Also, a change with time of
sensitivity (Eop) from that immediately after preparation was
5 determined. The storage stability was rated "good" when the
number of particles is not more than 5 or when the
sensitivity change was within 5%, and "poor" otherwise.
Debris appearing on the developed pattern was observed
under a scanning electron microscope (TDSEM) model S-7280H
10 (Hitachi Ltd.). The resist film was rated "good" when the
number of foreign particles was up to 10 per 100 |am 2 ,
"unacceptable" when from 11 to 15, and "poor" when more than
15.
Debris left after resist peeling was examined using a
15 surface scanner Surf-Scan 6220 (Tencol Instruments). A
resist-coated 8-inch wafer was subjected to entire exposure
rather than patterned exposure, processed in a conventional
manner, and developed with a 2.38% TMAH solution before the
resist film was peeled off (only the resist film in the
20 exposed area was peeled) . After the resist film was peeled,
the wafer was examined and rated "good" when the number of
foreign particles of greater than 0.20 \xm was up to 100,
"unacceptable" when from 101 to 150, and "poor" when more
than 150.
25 The results are shown in Table 5.
-90-
Table 1
Composition
(pbw)
Example
1
2
3
4
5
6
7
8
9
10
11
12
Polymer A
80
40
Polymer B
80
Polymer C
80
Polymer D
80
Polymer E
80
Polymer F
80
Polymer G
80
Polymer H
80
Polymer I
80
Polymer J
80
Polymer K
80
Polymer L
80
Polymer M
Polymer N
PAG1
3
3
3
2
PAG 2
3
2
3
3
PAG 3
3
1
o
PAG 4
2
2
A
PAG 5
1
1
*>
PAG 6
PAG 7
1
1
2
2
1
1
PAG 8
1
1
PAG 9
Dissolution
inhibitor
Basic compound A
0.3
0.3
0.3
0.3
0.3
0.15
0.3
0.3
Basic compound B
0.15
0.3
0.3
0.3
0.3
Organic acid
derivative A
0.5
0.5
0.5
Organic acid
derivative B
0.5
Surfactant A
0.25
0.25
0.25
0.25
0.25
0.25
Surfactant B
0.25
0.25
0.25
0. 25
0.25
0.25
UV absorber
Solvent A
385
385
385
385
385
385
385
280
382
385
280
385
Solvent B
105
105
-91-
Table 2
Composition
( pbw)
Example
13
14
15
16
17
18
19
20
21
22
23
24
Polymer A
40
60
Polymer B
60
75
Polymer C
40
40
Polymer D
70
40
60
40
Polymer E
40
10
Polymer F
Polymer G
40
Polymer H
Polymer I
10
20
Polymer J
Polymer K
40
Polymer L
40
20
70
Polymer M
40
20
Polymer N
80
PAG1
3
2
2
2
2
PAG2
2
2
2
2
PAG 3
3
3
2
PAG 4
z
*>
z
2
PAG 5
±
2
2
PAG 6
U . D
0 . 5
PAG 7
1.5
1.5
1
1
1
PAG 8
0.5
PAG 9
±
1
Crosslinker A
20
Dissolution
inhibitor
5
Basic compound A
0.15
0.3
0.3
0.3
Basic compound B
0.3
0.15
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Organic acid
derivative A
0.5
0.5
Organic acid
derivative B
0. 25
Surfactant A
0.25
0.25
0.25
0.25
0.25
0.25
Surfactant B
0. 25
0.25
0.25
0.25
0.25
UV absorber
0.5
Solvent A
280
385
385
385
280
385
385
385
280
385
280
385
Solvent B
105
105
105
105
-92-
Table 3
Composition
(pbw)
Comparative Example
1
2
3
Polymer A
80
40
Polymer E
80
Polymer K
40
PAG5
PAG 6
2.5
PAG 7
1
PAG8
2.5
2.5
PAG9
1
Dissolution inhibitor
Basic compound A
0.125
Basic compound B
0.125
0.125
Organic acid derivative A
0.5
Organic acid derivative B
Surfactant A
0. 25
0 . 25
Surfactant B
0
0.25
UV absorber
Solvent A
385
385
385
Solvent B
-93-
Table 4
Sensitivity
(mJ/cm 2 )
Resolution
Profile
DOF at
0.18 |im
Of f -focus
profile*
24 hr PED 1
dimensional
stability
(nm)
Example 1
37
0. 14
rectangular
1.0
rectangular
-10
Example 2
41
0. 14
rectangular
1.0
rectangular
10
Example 3
36
0. 14
rectangular
1.0
rectangular
-8
Example 4
35
0. 14
rectangular
1.0
rectangular
-8
Example 5
31
0. 16
rectangular
1.1
rectangular
-8
Example 6
33
0. 15
rectangular
1.0
rectangular
-10
Example 7
32
0. 14
rectangular
1.1
rectangular
-8
Example 8
35
0. 16
rectangular
1.1
rectangular
-8
Example 9
33
0. 14
rectangular
1.1
rectangular
-10
Example 10
39
0.15
rectangular
1.1
rectangular
-10
Example 11
31
0. 16
rectangular
1.0
rectangular
-9
Example 12
35
0.15
rectangular
1.1
rectangular
-10
Example 13
39
0.15
rectangular
1.0
rectangular
10
Example 14
31
0.14
rectangular
1.1
rectangular
-8
Example 15
33
0.14
rectangular
1.1
rectangular
-8
Example 16 1
35
0.15
rectangular
1.0
rectangular
-8
Example 17
33
0 .14
rectangular
1.1
rectangular
-10
Example 18
39
0.14
rectangular
1.0
rectangular
-8
Example 19
31
0.15
rectangular
0.8
rectangular
-10
Example 20
35
0 . 14
rect annular
^ ******* u uii y vi i *
1 . 0
rpptannnl at*
— ft
o
Example 21
39
0.15
rectangular
1.0
rectangular
-8
Example 22
31
0.14
rectangular
1.0
rectangular
-10
tiAauipic
J 3
0.14
rectangular
1 . 1
rectangular
-10
Example 24
32
0.18
rectangular
0.8
rectangular
-9
Comparative
Example 1
25
0.15
forward
taper
0.8
forward
taper
-10
Comparative
Example 2
32
0.15
rounded
head
0.8
rounded
head
-8
Comparative
Example 3
35
0.15
forward
taper
0.8
forward
taper
-10
* the shape of a pattern obtained when the focus was shifted -0.4 pun
to minus side upon DOF measurement at 0.18 \xm
-94-
Table 5
Dissolution
Application
100 day
storage
stability
Debris
after
development
Debris
after resist
peeling
Example 1
good
good
good
good
good
Example 2
good
good
good
good
good
Example 3
good
good
good
good
good
Example 4
good
good
good
good
good
Example 5
good
good
good
good
good
Example 6
good
good
good
good
good
Example 7
good
good
good
good
good
Example 8
good
good
good
good
good
Example 9
good
good
good
good
good
Example 10
good
good
good
good
good
Example 1 1
good
good
good
good
good
Example 12
good
good
good
good
good
Example 13
good
good
good
good
good
Example 14
good
good
good
good
good
Example 15
good
good
good
good
good
Example 16
good
good
good
good
good
Example 1 7
good
good
good
good
good
Example 1 8
good
good
good
good
good
Example 19
good
good
good
good
good
Example 20
good
good
good
good
good
Example 21
good
good
good
good
good
Example 22
good
good
good
good
good
Example 23
good
good |
good
good
good
Example 24
good
good
good
good
good
Comparative
Example 1
good
good
<30 days
(sensitivity
changed)
poor
unacceptable
Comparative
Example 2
good
good
good
unacceptable
poor
Comparative
Example 3
good
good
good
poor
poor
-95-
Examples 2 5-29 & Comparative Examples 4-6
Another experiment was performed by preparing resist
solutions according to the formulation shown in Table 6 and
baking resist coatings under different conditions.
5 The resist materials were filtered through a 0.2-jim
Teflon® filter, thereby giving resist solutions. The resist
solutions were spin-coated onto silicon wafers having an
organic antiref lection film (DUV-44, Brewer Science) of 800 A
thick coated thereon, so as to give a dry thickness of 0.6
10 \xm.
The coated wafers were then baked on a hot plate at
120° C for 90 seconds. The resist films were exposed to 2/3
annular illumination using an excimer laser stepper NSR-S202A
(Nikon Corporation, NA=0.6), then baked (PEB) at 130° C for 90
15 seconds, and developed with a solution of 2.38%
tetramethylammonium hydroxide in water. It was examined
whether or not a pattern was formed. The results are shown
in Table 7.
-96-
Table 6
Composition
(pbw)
Example
Comparative Example
25
26
27
28
29
4
5
6
Polymer F
80
Polymer H
40
80
80
80
80
Polymer I
40
80
40
Polymer J
40
PAG1
3
2
PAG 2
3
1
PAG 3
3
PAG 4
3
PAG 6
2
2
PAG 7
2
PAG8
2
Dissolution inhibitor
Basic compound A
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Basic compound B
Organic acid derivative A
0.5
Organic acid derivative B
Surfactant A
0.25
0.25
0.25
Surfactant B
0.25
0. 25
UV absorber
Solvent A
385
385
385
385
385
385
385
385
Solvent B
Table 7
Sensitivity
(mJ/cm 2 )
Resolution
(\xm)
Profile
Example 25
25
0. 14
rectangular
Example 26
23
0.15
rectangular
Example 27
24
0.15
rectangular
Example 28
24
0.14
rectangular
Example 29
24
0.14
rectangular
Comparative Example 4
19**
0. 20**
rounded head
Comparative Example 5
17**
0.20**
rounded head
Comparative Example 6
18**
0.20**
rounded head
** 0.18 [im unresolved; a sensitivity capable of resolving 0.20 \xm
being reported
-97-
There have been described chemically amplified resist
compositions comprising a specific benzenesulf onyldiazo-
methane containing a long-chain alkoxyl group at the
2 -position on its benzene ring as the photoacid generator.
The compositions have many advantages including improved
resolution, improved focus latitude, minimized line width
variation or shape degradation even on long-term PED, thermal
stability, minimized debris left after coating, development
and peeling, and improved pattern profile after development.
Because of high resolution, the compositions are suited for
microf abrication , especially by deep UV lithography.
Japanese Patent Application No. 2003-035077 is
incorporated herein by reference.
Although some preferred embodiments have been
described, many modifications and variations may be made
thereto in light of the above teachings. It is therefore to
be understood that the invention may be practiced otherwise
than as specifically described without departing from the
scope of the appended claims .
-98-
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